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“SI” redirects here. For other uses, see Si. Cover of brochure The International System of Units. The International System of Units (abbreviated SI from the French Le Système international d'unités) is the modern form of the metric system. It is the world's most widely used system of units, both in everyday commerce and in science. Look up si, Si, SI in Wiktionary, the free dictionary. ... Image File history File links SI_Brochure_Cover. ... The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ... In physics and metrology, units are standards for measurement of physical quantities that need clear definitions to be useful. ... This article does not cite any references or sources. ... Part of a scientific laboratory at the University of Cologne. ... The older metric system included several groups of units. The SI was developed in 1960 from the old metre-kilogram-second (mks) system, rather than the centimetre-gram-second (cgs) system, which, in turn, had a few variants. ‹ The template below (Unit of length) is being considered for deletion. ... Shown above is a computer-generated image of the International Prototype Kilogram (“IPK”). The IPK is the kilogram. ... Look up second in Wiktionary, the free dictionary. ... This article or section is in need of attention from an expert on the subject. ... The SI introduced several newly named units. The SI is not static — units are created and definitions are modified through international agreement among many nations as the technology of measurement progresses. The system is nearly universally employed, and most countries do not even maintain official definitions of any other units. A notable exception is the United States of America, which still uses many old units in addition to SI. In the United Kingdom, conversion to metric units is government policy, but the transition is not yet complete. Those countries that still recognise non-SI units (e.g. the US and UK) have redefined their traditional non-SI units in terms of SI units. Metrication or metrification refers to the introduction of the SI metric system as the international standard for physical measurements—a long-term series of independent and systematic conversions from the various separate local systems of weights and measures. ... Conversion of units refers to conversion factors between different units of measurement for the same quantity. ... Contents 1 History 1.1 Future development 2 Units 3 SI writing style 3.1 Spelling variations 4 Conversion factors 5 Cultural issues 5.1 Trade 6 See also 7 References 8 Further reading 9 External links [edit] History See main articles: metre, grave, kilogram, second, ampere, kelvin, mole and candela. The metric system was conceived by a group of scientists (among them, Antoine-Laurent Lavoisier, who is known as the "father of modern chemistry") which had been commissioned by King Louis XVI of France to create a unified and rational system of measures. After the French Revolution, the system was adopted by the new government.[1] On August 1, 1793, the National Convention adopted the new decimal "metre" with a provisional length as well as the other decimal units with preliminary definitions and terms. On April 7, 1795 (Loi du 18 germinal, an III) the terms gramme and kilogramme replaced the former terms "gravet" (correctly "milligrave") and "grave". On December 10, 1799 (a month after Napoleon's coup d'etat), the metric system was definitively adopted in France. ‹ The template below (Unit of length) is being considered for deletion. ... now. ... Shown above is a computer-generated image of the International Prototype Kilogram (“IPK”). The IPK is the kilogram. ... Look up second in Wiktionary, the free dictionary. ... Current can be measured by a galvanometer, via the deflection of a magnetic needle in the magnetic field created by the current. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... Photopic (black) and scotopic [1] (green) luminosity functions. ... The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ... Antoine-Laurent de Lavoisier (August 26, 1743 – May 8, 1794), the father of modern chemistry [1], was a French nobleman prominent in the histories of chemistry, finance, biology, and economics. ... Louis XVI Louis XVI (August 23, 1754 - January 21, 1793), was King of France and Navarre from 1774 until 1791, and then King of the French in 1791-1792. ... The French Revolution (1789–1815) was a period of political and social upheaval in the political history of France and Europe as a whole, during which the French governmental structure, previously an absolute monarchy with feudal privileges for the aristocracy and Catholic clergy, underwent radical change to forms based on... is the 213th day of the year (214th in leap years) in the Gregorian calendar. ... 1793 was a common year starting on Tuesday (see link for calendar). ... April 7 is the 97th day of the year in the Gregorian calendar (98th in leap years). ... 1795 was a common year starting on Thursday (see link for calendar). ... now. ... December 10 is the 344th day (345th in leap years) of the year in the Gregorian calendar, 21 days before the next year. ... 1799 was a common year starting on Tuesday (see link for calendar). ... Napoléon Bonaparte in the coup détat of 18 brumaire. ... The history of the metric system has seen a number of variations, whose use has spread around the world, to replace many traditional measurement systems. At the end of World War II a number of different systems of measurement were still in use throughout the world. Some of these systems were metric-system variations, while others were based on the Imperial and American systems. It was recognized that additional steps were needed to promote a worldwide measurement system. As a result the 9th General Conference on Weights and Measures (CGPM), in 1948, asked the International Committee for Weights and Measures (CIPM) to conduct an international study of the measurement needs of the scientific, technical, and educational communities. The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ... A system of measurement is a set of units which can be used to specify anything which can be measured and were historically important, regulated and defined because of trade and internal commerce. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... The Imperial units or the Imperial system is a collection of English units, first defined in the Weights and Measures Act of 1824, later refined (until 1959) and reduced. ... Metrication or metrification refers to the introduction of the SI metric system as the international standard for physical measurements—a long-term series of independent and systematic conversions from the various separate local systems of weights and measures. ... The General Conference on Weights and Measures is the English name of the Conférence générale des poids et mesures (CGPM, never GCWM). ... The International Committee for Weights and Measures is the English name of the Comité international des poids et mesures (CIPM, sometimes written in English Comité International des Poids et Mesures). ... Based on the findings of this study, the 10th CGPM in 1954 decided that an international system should be derived from six base units to provide for the measurement of temperature and optical radiation in addition to mechanical and electromagnetic quantities. The six base units recommended were the metre, kilogram, second, ampere, Kelvin degree (later renamed the kelvin), and the candela. In 1960, the 11th CGPM named the system the International System of Units, abbreviated SI from the French name: Le Système international d'unités. The seventh base unit, the mole, was added in 1971 by the 14th CGPM. ‹ The template below (Unit of length) is being considered for deletion. ... Shown above is a computer-generated image of the International Prototype Kilogram (“IPK”). The IPK is the kilogram. ... Look up second in Wiktionary, the free dictionary. ... Current can be measured by a galvanometer, via the deflection of a magnetic needle in the magnetic field created by the current. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... Photopic (black) and scotopic [1] (green) luminosity functions. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... [edit] Future development The ISO standard ISO 31 contains recommendations for the use of the International System of Units; for applications in electrical applications additionally the IEC standard IEC 60027 has to be taken into account. As of 2008 work is proceeding [citation needed] to integrate both standards into an joint standard ISO/IEC 80000 to be referred as International System of Quantities (ISQ). “ISO” redirects here. ... International Standard ISO 31 (Quantities and units, International Organization for Standardization, 1992) is the most widely respected style guide for the use of units of measurement, and formulas involving them, in scientific and educational documents worldwide. ... The International Electrotechnical Commission (IEC) is an international standards organization dealing with electrical, electronic and related technologies. ... International Standard ISO 80000 (Quantities and units, International Organization for Standardization) is the most widely respected style guide for the use of units of measurement, and formulas involving them, in scientific and educational documents worldwide. ... [edit] Units Main articles: SI base unit, SI derived unit, and SI prefix The international system of units consists of a set of units together with a set of prefixes. The units of SI can be divided into two subsets. There are seven base units. Each of these base units are nominally dimensionally independent. From these seven base units several other units are derived. In addition to the SI units there are also a set of non-SI units accepted for use with SI. The SI system of units defines seven SI base units: physical units defined by an operational definition. ... SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. ... An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... The SI system of units defines seven SI base units: physical units defined by an operational definition. ... SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. ... The following units are not SI units but are accepted for use with the International System. ... SI base units[2] Name Symbol Quantity meter m length kilogram kg mass second s time ampere A electric current kelvin K thermodynamic temperature mole mol amount of substance candela cd luminous intensity A prefix may be added to units to produce a multiple of the original unit. All multiples are integer powers of ten. For example, kilo- denotes a multiple of a thousand and milli- denotes a multiple of a thousandth hence there are one thousand millimetres to the metre and one thousand metres to the kilometre. The prefixes are never combined: a millionth of a kilogram is a milligram not a microkilogram. The metre, or meter (symbol: m) is the SI base unit of length. ... Look up length, width, breadth in Wiktionary, the free dictionary. ... Shown above is a computer-generated image of the International Prototype Kilogram (“IPK”). The IPK is the kilogram. ... This article or section is in need of attention from an expert on the subject. ... Look up second in Wiktionary, the free dictionary. ... Look up time in Wiktionary, the free dictionary. ... Current can be measured by a galvanometer, via the deflection of a magnetic needle in the magnetic field created by the current. ... In electricity, current refers to electric current, which is the flow of electric charge. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... Thermodynamic temperature is the absolute measure of temperature and is one of the principal parameters of thermodynamics. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... The amount of substance, n, of a sample or system is a physical quantity which is proportional to the number of elementary entities present. ... Photopic (black) and scotopic [1] (green) luminosity functions. ... Luminous intensity is a measure of the energy emitted by a light source in a particular direction. ... An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... SI Prefixes Name yotta- zetta- exa- peta- tera- giga- mega- kilo- hecto- deca- Symbol Y Z E P T G M k h da Factor 1024 1021 1018 1015 1012 109 106 103 102 101 Name deci- centi- milli- micro- nano- pico- femto- atto- zepto- yocto- Symbol d c m µ n p f a z y Factor 10-1 10-2 10-3 10-6 10-9 10-12 10-15 10-18 10-21 10-24 An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... Yotta (symbol Y) is a SI prefix in the SI system of units denoting 1024 or 1 000 000 000 000 000 000 000 000. ... Zetta (symbol Z) is a SI prefix in the SI system of units denoting 1021 or 1 000 000 000 000 000 000 000. ... Exa (symbol E) is a prefix in the SI system of units denoting 1018 or 1 000 000 000 000 000 000. ... This article describes the SI prefix peta. ... Tera (symbol: T) is a prefix in the SI system of units denoting 1012, or 1 000 000 000 000. ... Giga (symbol: G) is a prefix in the SI system of units denoting 109, or 1 000 000 000. ... Mega (symbol M) is a SI prefix in the SI system of units denoting a factor of 106, i. ... Kilo (symbol: k) is a prefix in the SI system denoting 103 or 1,000. ... Hecto (symbol h) is a SI prefix in the SI system of units denoting a factor of 102 (100). ... This article is about the SI prefix. ... Deci- is a Latin numerical prefix meaning 10. ... Centi (symbol c) is a SI prefix in the SI system of units denoting a factor of 10-2, or 1/100. ... Milli (symbol m) is a SI prefix in the SI system of units denoting a factor of 10-3, or 1/1,000. ... Micro is a SI prefix in the SI system of units denoting a factor of 10−6 (one millionth). ... Look up nano- in Wiktionary, the free dictionary. ... For other meanings of Pico see Pico (disambiguation) Pico (symbol p) is a prefix in the SI system of units denoting a factor of 10-12. ... Femto is a prefix (see all prefixes) to a unit and means that it is 10-15 times this unit, or, one quindecillionth (European) or one quadrillionth (American). ... Atto- (symbol a) is an SI prefix to a unit and means that it is 10-18 times this unit. ... Zepto (symbol z) is a prefix in the SI system of units denoting a factor of 10-21. ... Yocto (symbol y) is a SI prefix in the SI system of units denoting a factor of 10-24. ... [edit] SI writing style Symbols do not have an appended period/full stop (.) unless at the end of a sentence. Symbols are written in upright Roman type (m for metres, L for litres), so as to differentiate from the italic type used for mathematical variables (m for mass, l for length). Symbols for units are written in lower case, except for symbols derived from the name of a person. For example, the unit of pressure is named after Blaise Pascal, so its symbol is written "Pa" whereas the unit itself is written "pascal". The one exception is the litre, whose original symbol "l" is unsuitably similar to the numeral "1" or the uppercase letter "i" (depending on the typeface used), at least in many English-speaking countries. The American National Institute of Standards and Technology recommends that "L" be used instead, a usage which is common in the US, Canada, Australia, and New Zealand (but not elsewhere). This has been accepted as an alternative by the CGPM since 1979. The cursive "ℓ" is occasionally seen, especially in Japan and Greece, but this is not currently recommended by any standards body. For more information, see Litre. The SI rule for pluralising units is that symbols of units are not pluralised[3], for example "25 kg" (not "25 kgs"). The American National Institute of Standards and Technology has defined guidelines for using the SI units in its own publications and for other users of the SI[4]. These guidelines give guidance on pluralizing unit names: the plural is formed by using normal English grammar rules, for example, "henries" is the plural of "henry". The units lux, hertz, and siemens are exceptions from this rule: they remain the same in singular and plural. Note that this rule only applies to the full names of units, not to their symbols. A space separates the number and the symbol, e.g. "2.21 kg", "7.3×102 m²", "22 K" [5]. Exceptions are the symbols for plane angular degrees, minutes and seconds (°, ′ and ″), which are placed immediately after the number with no intervening space. Spaces may be used as a thousands separator (1 000 000) in contrast to commas or periods (1,000,000 or 1.000.000) in order to reduce confusion resulting from the variation between these forms in different countries. In print, the space used for this purpose is typically narrower than that between words. The 10th resolution of CGPM in 2003 declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line". In practice, the decimal point is used in English, and the comma in most other European languages. Symbols for derived units formed from multiple units by multiplication are joined with a space or centre dot (·), e.g. "N m" or "N·m". Symbols formed by division of two units are joined with a solidus (⁄), or given as a negative exponent. For example, the "metre per second" can be written "m/s", "m s−1", "m·s−1" or A solidus should not be used if the result is ambiguous, i.e. "kg·m−1·s−2" is preferable to "kg/m·s²". (Taylor (§ 6.1.6) specifically calls for the use of a solidus.[4] Many computer users will type the / character provided on American computer keyboards, which in turn produces the Unicode character U+002F, which is named solidus but is distinct from the Unicode solidus character, U+2044. Taylor does not offer suggestions about which mark should be used when more sophisticated typesetting options are available.) In Chinese, Japanese, and Korean language computing (CJK), some of the commonly used units, prefix-unit combinations, or unit-exponent combinations have been allocated predefined single characters taking up a full square. Unicode includes these in its CJK Compatibility and Letterlike Symbols subranges for back compatibility, without necessarily recommending future usage. When writing dimensionless quantities, the terms 'ppb' (parts per billion) and 'ppt' (parts per trillion) are recognised as language-dependent terms since the value of billion and trillion can vary from language to language. SI therefore recommends avoiding these terms [2]. However, no alternative is suggested by BIPM. Roman type has two separate meanings in typography, both of which refer to the fact that the capital letters of a Roman font have an appearance similar to those used for lettering stone in ancient Rome: Roman type can refer to one of the major families of traditional typefaces as... This article or section does not adequately cite its references or sources. ... Minuscule, or lower case, is the smaller form (case) of letters (in the Roman alphabet: a, b, c, ...). Originally alphabets were written entirely in majuscule (capital) letters which were spaced between well-defined upper and lower bounds. ... This article is about pressure in the physical sciences. ... Blaise Pascal (pronounced ), (June 19, 1623 – August 19, 1662) was a French mathematician, physicist, and religious philosopher. ... The former Weights and Measures office in Middlesex, England. ... The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Youngs modulus and tensile strength). ... The litre or liter (see spelling differences) is a unit of volume. ... The following is a list of sovereign states and territories where English is an official language, in order of population. ... NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ... The General Conference on Weights and Measures is the English name of the Conférence générale des poids et mesures (CGPM, never GCWM). ... Also: 1979 by Smashing Pumpkins. ... A standards organization, also sometimes referred to as a standards body, a standards development organization or SDO (depending on what is being referenced), is any entity whose primary activities are developing, coordinating, promulgating, revising, amending, reissuing, interpreting, or otherwise maintaining standards that address the interests of a wide base of... The litre or liter (see spelling differences) is a unit of volume. ... NIST logo The National Institute of Standards and Technology (NIST, formerly known as The National Bureau of Standards) is a non-regulatory agency of the United States Department of Commerce’s Technology Administration. ... English grammar is a body of rules specifying how meanings are created in English. ... An inductor. ... The lux (symbol: lx) is the SI derived unit of illuminance or illumination. ... This article is about the SI unit of frequency. ... The siemens (symbol: S) is the SI derived unit of electric conductance. ... The decimal separator is a symbol used to mark the boundary between the integral and the fractional parts of a decimal numeral. ... A space is a punctuation convention for providing interword separation in some scripts, including the Latin, Greek, Cyrillic, and Arabic. ... The General Conference on Weights and Measures is the English name of the Conférence générale des poids et mesures (CGPM, never GCWM). ... This article or section does not cite its references or sources. ... This article does not cite any references or sources. ... The term comma has various uses; comma is the name used for one of the punctuation symbols: , The term comma is also used in music theory for various small intervals that arise as differences between approximately equal intervals. ... Map showing approximate current distribution of languages in Europe, but with emphasis on locations of minority languages Most of the many languages of Europe belong to the Indo-European language family. ... An interpunct · is a small dot used for interword separation in ancient Latin script, being perhaps the first consistent visual representation of word boundaries in written language. ... A solidus, oblique or slash, /, is a punctuation mark. ... In mathematics, exponentiation is a process generalized from repeated multiplication, in much the same way that multiplication is a process generalized from repeated addition. ... It has been suggested that Keystroke be merged into this article or section. ... This article is mainly about the spoken Korean language. ... CJK is a collective term for Chinese, Japanese, and Korean, which comprise the main East Asian languages. ... The Unicode Standard, Version 5. ... Billion may mean: 1,000,000,000 (one thousand million; ), used by most English-speaking countries (American and usual modern British meaning) 1,000,000,000,000 (one million million; ), used by most other countries outside Asia (older British meaning). ... The numeral trillion refers to one of two number values, depending on the context of where and how it is being used. ... The long and short scales are two different numerical systems used throughout the world: Short scale is the English translation of the French term échelle courte. ... [edit] Spelling variations Several nations typically use the spellings meter and liter instead of metre and litre in keeping with standard American English spelling, which also corresponds to the official spelling used in several other languages, such as German, Dutch, Swedish, etc. In addition, the official US spelling for the SI prefix "deca" is deka.[6] In some English-speaking countries, the unit "ampere" is often shortened to amp (singular) or amps (plural). For other uses, see American English (disambiguation). ... An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... [edit] Conversion factors The relationship between the units used in different systems is determined by convention or from the basic definition of the units. Conversion of units from one system to another is accomplished by use of a conversion factor. There are several compilations of conversion factors; see, for example Appendix B of NIST SP 811.[4] Conversion of units refers to conversion factors between different units of measurement for the same quantity. ... [edit] Cultural issues The worldwide adoption of the metric system as a tool of economy and everyday commerce was based to some extent on the lack of customary systems in many countries to adequately describe some concepts, or as a result of an attempt to standardise the many regional variations in the customary system. International factors also affected the adoption of the metric system, as many countries increased their trade. Scientifically, it provides ease when dealing with very large and small quantities because it lines up so well with the decimal numeral system. The decimal (base ten or occasionally denary) numeral system has ten as its base. ... A numeral is a symbol or group of symbols, or a word in a natural language that represents a number. ... There are many units in everyday and scientific use that are not derived from the seven SI base units—metre, kilogram, second, ampere, kelvin, mole and candela—combined with the SI prefixes. In some cases these deviations have been approved by the BIPM.[3] Examples include: The many units of time — minute (min), hour (h), day (d) — in use besides the SI second, and are specifically accepted for use according to table 6.[4] The year is specifically not included but has a recommended conversion factor.[5] The Celsius temperature scale; kelvins are rarely employed in everyday use. Electric energy is often billed in kilowatt-hours instead of megajoules. The nautical mile and knot (nautical mile per hour) used to measure travel distance and speed of ships and aircraft (1 International nautical mile = 1852 m or approximately 1 minute of latitude at the equator). In addition to these, Annex 5 of the Convention on International Civil Aviation permits the "temporary use" of the foot for altitude. Astronomical distances measured in astronomical units, parsecs and light-years instead of, say, petametres (a light-year is about 9.461 Pm or about 9 461 000 000 000 000 m). Atomic scale units used in physics and chemistry, such as the ångström, electronvolt, atomic mass unit, and barn. Some physicists still use the centimetre-gram-second (CGS) units, with their associated non-SI electric units. In some countries, the informal cup measurement has become 250 ml. Likewise, a 500 g "metric pound" is used in many countries. Liquids, especially alcoholic ones, are often sold in units whose origins are historical, e.g. beer in pints in the UK, champagne in Jeroboams in France. In the US, blood glucose measurements are recorded in milligrams per decilitre (mg/dL); in Canada and Europe, the standard is millimole per litre (mmol/L or mM (millimolar). Blood pressure is measured in mmHg instead of Pa. The fine-tuning that has happened to the metric base unit definitions over the past 200 years, as experts have tried periodically to find more precise and reproducible methods, does not affect the everyday use of metric units. Since most non-SI units in common use, such as the US customary units, are nowadays defined in terms of SI units, any change in the definition of the SI units results in a change of the definition of the older units as well. Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Electrical energy can refer to several closely related things. ... The watt-hour (symbol W·h) is a unit of energy. ... A nautical mile or sea mile is a unit of length. ... A knot is a unit of speed, abbreviated kt or kn. ... The Convention on International Civil Aviation, also known as the Chicago Convention, established the International Civil Aviation Organization (ICAO), a specialized agency of the United Nations charged with coordinating and regulating international air travel. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... Altitude is the elevation of an object from a known level or datum. ... Astronomical distances are simply so massively huge as to defy the imagination and boggle the mind. ... The astronomical unit (AU or au or a. ... A parsec is the distance from the Earth to an astronomical object which has a parallax angle of one arcsecond. ... A light-year, symbol ly, is the distance light travels in one year: exactly 9. ... An Ã¥ngström or aangstroem (the official transliteration), or angstrom (symbol Ã…) is a non-SI unit of length that is internationally recognized, equal to 0. ... The electronvolt (symbol eV) is a unit of energy. ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... A barn (symbol b) is a unit of area. ... Not to be confused with physician, a person who practices medicine. ... This article or section is in need of attention from an expert on the subject. ... The cup is a unit of measurement for volume, used in cooking to measure bulk foods, such as chopped vegetables (dry measurement), and liquids (fluid measurement). ... The pound or pound-mass (abbreviations: lb, lbm, or sometimes in the United States, #) is a unit of mass (sometimes called weight in everyday parlance) in a number of different systems, including English units, Imperial units, and United States customary units. ... This article does not cite any references or sources. ... In medicine, blood sugar is a term used to refer to levels of glucose in the blood. ... A sphygmomanometer, a device used for measuring arterial pressure. ... The U.S. customary units (more commonly known in the US as English units or standard units) are the non-metric units of measurement that are presently used in the United States, in some cases alongside the metric system of units. ... [edit] Trade The European Union has a directive[7] banning non-SI markings after 31 December 2009 on any goods imported into the European Union. This applies to all markings on products, enclosed directions and papers, packaging, and advertisements. However, on September 11, 2007, the EU announced that the United Kingdom would be excepted from this directive, and Imperial measurements would still be permitted.[8] is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... 2009 (MMIX) will be a common year starting on Thursday of the Gregorian calendar. ... is the 254th day of the year (255th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... The Imperial units or the Imperial system is a collection of English units, first defined in the Weights and Measures Act of 1824, later refined (until 1959) and reduced. ... [edit] See also Metrology Units of measurement History of measurement Orders of magnitude Metrication Metrication in the United States Organisations International Bureau of Weights and Measures (BIPM) Institute for Reference Materials and Measurements (IRMM) CODATA Standards and conventions SI base unit SI derived unit SI prefix Convention du Mètre ISO 31 ISO 1000 ISO/IEC 80000 Coordinated Universal Time (UTC) v • d • e Systems of measurement Metric systems International System of Units · centimetre-gram-second units · metre-tonne-second units · gravitational units Natural units Geometric unit systems · Planck units · Stoney units · "Schrödinger" units · Atomic units · Electronic units · Quantum electrodynamical units Customary systems Avoirdupois units · Troy units · Apothecaries' units · English units · Imperial units · US customary units · Danish units · Dutch units · Finnish units · French units · German units · Maltese units · Norwegian units  · Scottish units · Spanish units · Swedish units · Polish units · Romanian units · Russian units · Tatar units · Hindu units · Pegu units · Chinese units · Japanese units Ancient systems Greek units · Roman units · Egyptian units · Hebrew units · Arabic units · Mesopotamian units · Persian units · Harappan units Other systems Non-standard measurement units · Mesures usuelles Metrology (from Greek metron (measure), and -logy) is the science of measurement. ... The former Weights and Measures office in Middlesex, England. ... Some human-referenced units of measurement Units of measurement were among the earliest tools invented by humans. ... An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... Metrication or metrification refers to the introduction of the SI metric system as the international standard for physical measurements—a long-term series of independent and systematic conversions from the various separate local systems of weights and measures. ... This label, on a bottle of Head & Shoulders shampoo, illustrates the conflicted state of U.S. metrication in the early 21st century. ... The International Bureau of Weights and Measures is the English name of the Bureau international des poids et mesures (BIPM, often written in English Bureau International des Poids et Mesures), a standards organisation, one of the three organizations established to maintain the International System of Units (SI) under the terms... The Institute for Reference Materials and Measurements or IRMM, located in Geel, Belgium, is one of the seven institutes of the Joint Research Centre (JRC), a Directorate-General of the European Commission (EC). ... CODATA (Committee on Data for Science and Technology) was established in 1966 as an interdisciplinary committee of the International Council of Science (ICSU), formerly the International Council of Scientific Unions. ... The SI system of units defines seven SI base units: physical units defined by an operational definition. ... SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. ... An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... The Convention du Mètre of May 20, 1875 is an international treaty that established what is now known as the SI system of units. ... International Standard ISO 31 (Quantities and units, International Organization for Standardization, 1992) is the most widely respected style guide for the use of units of measurement, and formulas involving them, in scientific and educational documents worldwide. ... International Standard ISO 1000 (SI units and recommendations for the use of their multiples and of certain other units, International Organization for Standardization, 1992) is the ISO standard describing the International System of Units (SI). ... International Standard ISO 80000 (Quantities and units, International Organization for Standardization) is the most widely respected style guide for the use of units of measurement, and formulas involving them, in scientific and educational documents worldwide. ... “UTC” redirects here. ... A system of measurement is a set of units which can be used to specify anything which can be measured and were historically important, regulated and defined because of trade and internal commerce. ... The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ... This article or section is in need of attention from an expert on the subject. ... The metre-tonne-second or mts system of units is a system of physical units introduced in the Soviet Union in 1933, but abolished in 1955. ... The deprecated unit kilogram-force (kgf) or kilopond (kp) is the force exerted by one kilogram of mass in standard Earth gravity (defined as exactly 9. ... In physics, natural units are physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. ... In physics, especially in the general theory of relativity, geometrized units or geometric units constitute a physical unit system in which all physical quantities are identified with geometric quantities such as areas, lengths, dimensionless numbers, path curvatures, or sectional curvatures. ... In physics, Planck units are physical units of measurement defined exclusively in terms of the five universal physical constants shown in the table below in such a manner that all of these physical constants take on the numerical value of one when expressed in terms of these units. ... In physics, natural units are physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. ... In physics, natural units are physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. ... Atomic units (au) form a system of units convenient for electromagnetism, atomic physics, and quantum electrodynamics, especially when the focus is on the properties of electrons. ... In physics, natural units are physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. ... In physics, natural units are physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. ... The avoirdupois (IPA: ; French:) system is a system of weights (or, properly, mass) based on a pound of sixteen ounces. ... Troy weight is a system of units of mass customarily used for precious metals, black powder, and gemstones. ... The apothecaries system of mass is an obsolete system formerly used by apothecaries (now called pharmacists or chemists) in English-speaking countries. ... English unit is the American name for a unit in one of a number of systems of units of measurement, some obsolete, and some still in use. ... The Imperial units or the Imperial system is a collection of English units, first defined in the Weights and Measures Act of 1824, later refined (until 1959) and reduced. ... U.S. customary units, also known in the United States as English units[1] (but see English unit) or standard units, are units of measurement that are currently used in the USA, in some cases alongside units from SI (the International System of Units — the modern metric system). ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article needs to be cleaned up to conform to a higher standard of quality. ... In Finland, approximate units of measure derived from body parts and were used for a long time, some being later standardised for the purpose of commerce. ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article needs to be cleaned up to conform to a higher standard of quality. ... In modern usage, metric is used almost exclusively in commercial transactions. ... As in the case of the Danes the Norwegians earliest standards of measure can be derived from their ship burials. ... Several native system of weights and measures were used in Scotland. ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Ancient Polish weights and measures included: Garniec [1] Grzywna [2] and [3] KamieÅ„ [4] Korzec [5] Krok [6] Kwarta [7] Kwartnik [8] Łan [9] Łaszt [10] Ławka [11] Łokieć [12] Łut [13] Morga [14] Pacierz [15] PiÄ™dź [16] Skojec [17] Staje [18] Stopa [19] Wiardunek [20] ZdrowaÅ›ka [21... The measures of the old Romanian system varied greatly not only between the three Romanian states (Wallachia, Moldavia, Transylvania), but sometimes also inside the same country. ... Obsolete Russian weights and measures were used in Imperial Russia and after the Russian Revolution until they were replaced in the Soviet Union by a metric system in 1924. ... Obsolete Tatar weights and measures were used by Tatars until 1924, when they were replaced in the Soviet Union by the SI units. ... Old Indian measures are still in use today, primarily for religious purposes in Hinduism and Jainism. ... This article or section does not cite any references or sources. ... The Chinese units (Chinese: 市制; Hanyu Pinyin: ; literally market system) are the customary and traditional units of measure used in China. ... Shakkan-hō ) is the traditional Japanese system of measurement. ... Ancient Greek weights and measures - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... The Roman system of measurement was built on the Greek system with Egyptian influences. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Weight Reduced to English troy-weight, the Hebrew weights were: Gerah (Lev. ... The Arabic system of measurement is based on the Persian system. ... Originally Ancient Mesopotamian weights and measures came from a collection of city states loosely organized by family, tribe and occupation. ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article does not cite its references or sources. ... Unusual units of measurement are sometimes used by scientists, especially physicists and mathematicians, and other technically-minded people such as engineers and programmers, as bits of dry humor combined with putative practical convenience. ... Mesures usuelles (French for customary measurements) were a system of measurement introduced to act as compromise between metric system and traditional measurements. ... [edit] References ^ The name "kilogram". Retrieved on 2006-07-25. ^ Barry N. Taylor, Ed. [2001]. The International System of Units (SI). Washington, DC: National Institute of Standards and Technology, 9. Retrieved on 2007-6-27.  ^ Bureau International des Poids et Mesures (2006). "The International System of Units (SI)". 8th ed.. Retrieved on 2006-07-14. ^ a b c Taylor, B.N. (1995). "NIST Special Publication 811: Guide for the Use of the International System of Units (SI)". National Institute of Standards and Technology. Retrieved on 2006-06-09. ^ Taylor, B. N.. NIST Guide to SI Units - Rules and Style Conventions. National Institute of Standards and Technology. Retrieved on 2007-04-12. ^ Definitions of the SI units: The twenty SI prefixes. Retrieved on 2007-04-12. ^ Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC, as amended with Directive 89/617/EEC (which changed the cutoff date in article 3.2 to 31 December 1999) and Directive 1999/103/EC (which further changed the date to 31 December 2009). Retrieved on 2006-07-24. ^ [1] Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 206th day of the year (207th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 195th day of the year (196th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... June 9 is the 160th day of the year in the Gregorian calendar (161st in leap years), with 205 days remaining. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... This article is about the year. ... is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... 2009 (MMIX) will be a common year starting on Thursday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 205th day of the year (206th in leap years) in the Gregorian calendar. ... [edit] Further reading International Union of Pure and Applied Chemistry (1993). Quantities, Units and Symbols in Physical Chemistry (2nd Edn). Oxford: Blackwell Science. ISBN 0-632-03583-8. Electronic version. IUPAC logo The International Union of Pure and Applied Chemistry (IUPAC) (Pronounced as eye-you-pack) is an international non-governmental organization established in 1919 devoted to the advancement of chemistry. ... Quantities, Units and Symbols in Physical Chemistry (ISBN 0632035838), also known as the Green Book, edited by I. Mills, et al. ... [edit] External links Official BIPM Bureau International des Poids et Mesures (SI maintenance agency) (home page) BIPM brochure (SI reference) ISO 1000:1992 SI units and recommendations for the use of their multiples and of certain other units ISO 31/1000/80000 NIST Official Publications NIST Special Pub 814: Interpretation of the SI for the United States and Federal Government Metric Conversion Policy Weights and Measures Act, Canada IEEE/ASTM SI 10-2002 Standard for Use of the International System of Units (SI): The Modern Metric System (ANSI approved, joint IEEE/ASTM standard) Rules for SAE Use of SI (Metric) Units Information International System of Units at the Open Directory Project History LaTeX SIunits package manual gives a historical background to the SI system. Pro-metric pressure groups The UK Metric Association The US Metric Association One Metre: Metric in Canada Canadian Metric Association Metrication US Pro-customary measures pressure groups Pro-customary measures groups at the Open Directory Project The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ... An interest group (also called an advocacy group, lobbying group, pressure group (UK), or special interest) is a group, however loosely or tightly organized, doing advocacy: those determined to encourage or prevent changes in public policy without trying to be elected. ... The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ... Categories: All articles with unsourced statements