A fluid ounce is a unit of volume in both the Imperial system of units and the U.S. customary units system. The volume of a solid object is the three-dimensional concept of how much space it occupies, often quantified numerically. ... The Imperial units are an irregularly standardized system of units that have been used in the United Kingdom and its former colonies, including the Commonwealth countries. ... U.S. customary units, commonly known in the United States as English units or standard units, are units of measurement that are currently used in the U.S., in some cases alongside units from SI (the International System of Units—the modern metric system). ...

Definition

The two types of ounces have slightly different definitions:

• The Imperial fluid ounce is 1/160 of an imperial gallon or 1/20 of an imperial pint or 8 fluid drams, about 1.734 cubic inches or 28.4130625 millilitres.^[1] This volume of water weighs very nearly 1 avoirdupois ounce (it is the volume occupied by one ounce at 62 °F (16.7 °C), weighed in air with brass weights).

• The U.S. fluid ounce is defined to be 1/128 of a U.S. gallon or 1/16 of a U.S. pint, exactly 1.8046875 cubic inches or 29.5735295625 milliliters. This volume of cool, pure water weighs about 1.04 avoirdupois ounces (29.5 g).
• U.S. regulation 21 CFR 101.9(b)(5)(viii) also defines a fluid ounce as exactly 30 ml, but this is for use in nutrition labeling only.^[2] These two definitions, one using English units and one metric, are not meant to concur exactly and are a common source of confusion.

In either system, the unit is often abbreviated as fl. oz., oz. fl., or fl oz. It is common to refer to the unit simply as "ounce", especially in cases where no confusion can occur with the unit of weight. The gallon (abbreviation: gal) is a unit of volume. ... The pint is a unit of volume or capacity. ... The dram (American spelling) or drachm (British spelling) is a small imperial unit of volume; it is also called the fluidram (contraction of fluid dram). ... A cubic inch is the volume of a cube which is one inch long on each edge. ... The millilitre is the equivalent of a cubic centimetre. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The avoirdupois (IPA: ; French:) system is a system of weights (or, properly, mass) based on a pound of sixteen ounces. ... The ounce (abbreviation: oz) is the name of a unit of mass in a number of different systems, including various systems of mass that form part of English units, Imperial units, and United States customary units. ...

Etymology

The word ounce derives originally from a word meaning "one" (originally "one" twelfth part of a troy pound)^[3]. The word unit is also derived from the same original word, unus (one). [1] [2] In effect, the phrase "fluid ounce" is essentially equivalent to "liquid unit". Troy weight is a system of units of mass customarily used for precious metals and gemstones. ...

References

1. ^ The Units of Measurement Regulations 1995 (2000-09-20). Retrieved on 2006-04-18.
2. ^ Food and Drug Administration, HHS (PDF). Retrieved on 2006-04-18.
3. ^ Definition of ounce, from the Merriam-Webster online.

For the Manfred Mann album, see 2006 (album). ... is the 108th day of the year (109th in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... is the 108th day of the year (109th in leap years) in the Gregorian calendar. ...

See also

• Conversion of units#Volume