The Locrian mode is a musical mode or diatonic scale. It may be considered a minor scale with the second and fifth scale degrees lowered a semi-tone. The Locrian mode may also be considered as a scale beginning on the seventh scale degree of any Ionian, or major scale. In music, a mode is an ordered series of musical intervals, which, along with the key or tonic, define the pitches. ... In music theory, a diatonic scale (from the Greek diatonikos, to stretch out; also known as the heptatonia prima; set form 7-35) is a seven-note musical scale comprising five whole-tone and two half-tone steps, in which the half tones are maximally separated. ... A minor scale in musical theory is a diatonic scale whose third scale degree is an interval of a minor third above the tonic. ... The musical interval of a half step, semitone, or minor second is the relationship between the leading tone and the first note (the root or tonic) in a major scale. ... The Ionian mode is a musical mode or diatonic scale. ... In music theory, the major scale (or major mode) is one of the diatonic scales. ...

Some examples:

• The B Locrian mode starts on B and contains the same notes as C Major scale. (B, C, D, E, F, G, A, B)
• The E Locrian mode starts on E and contains the same notes as F Major Scale. (E, F, G, A, B♭, C, D, E)

The Locrian mode is the only modern diatonic mode in which the tonic chord is a diminished chord, resulting in a tonic chord that is considered dissonant. For example, the tonic chord of B Locrian is spelled B, D, F. The interval between the tonic (B) and the dominant (F) is a diminished fifth or tritone. The tonic is the first note of a musical scale, and in the tonal method of music composition it is extremely important. ... Generally speaking, a diminished chord is a chord which has a diminished fifth in it. ... In poetry, dissonance is the deliberate avoidance of patterns of repeated vowel sounds (see assonance). ... The word dominant has several possible meanings: In music theory, the dominant or dominant note (second most important) of a key is that which is a perfect fifth above the tonic; in just intonation the note whose pitch is 1. ... The augmented fourth between C and F# forms a tritone. ...

The Locrian mode was of mainly theoretical importance in classical music before the 1850s because of the large amount of dissonance created within the scale and its corresponding chord. In more recent musical pieces, the dissonance or musical imbalance created by the Locrian scale and chord have fallen back in favour (especially in Jazz) in order to create a sense of large tension. Classical music is a broad, somewhat imprecise term, referring to music produced in, or rooted in the traditions of, European art, ecclesiastical and concert music, encompassing a broad period from roughly 1000 to the present day. ... // Events and Trends Technology Production of steel revolutionised by invention of the Bessemer process Benjamin Silliman fractionates petroleum by distillation for the first time First transatlantic telegraph cable laid First safety elevator installed by Elisha Otis Science Charles Darwin publishes The Origin of Species, putting forward the theory of evolution... Fingering for a C-major trichord on a guitar in standard tuning (assuming all six strings are played). ... Jazz is an original American musical art form originating around the start of the 20th century in New Orleans, rooted in Western music technique and theory, and is marked by the profound cultural contributions of African Americans. ...

Heavy metal musicians also use Locrian mode; one notable example is the guitar introduction to Metallica's Enter Sandman. Another example, more from the progressive hard rock genre, is the first section of the instrumental YYZ by Rush: the synthesizer melody is in C Locrian, over a guitar riff based on the C-Gb tritone. Heavy metals, in chemistry, are chemical elements of a particular range of atomic weights. ... Metallica is an American metal band formed in October 1981. ... This article or section is missing references or citation of sources. ... YYZ is an instrumental song that eventually turns into a drum and bass solo that appears on the Rush album Moving Pictures. ... Rush is a Canadian progressive rock band comprising bassist, keyboardist and vocalist Geddy Lee, guitarist Alex Lifeson, and drummer and lyricist Neil Peart (IPA: ). Rush formed in the summer of 1968, in Willowdale, Ontario (a northern suburb of Toronto) by Lifeson, Lee, and John Rutsey. ...

The Locrian mode comes from the music theory of ancient Greece. However, what is now called the Locrian mode was what the Greeks called the Mixolydian mode. The original Greek Locrian mode seems to have been tuned to a natural A mode, but how it differed from the Aeolian and Hypodorian modes is unclear. Ancient Greece is the period of Greek history spanning much of the Mediterranean and Black Sea basins and lasting for close to a millennium, until the rise of Christianity. ... The Mixolydian mode is a musical mode or diatonic scale. ... The aeolian mode is a musical mode or diatonic scale. ... The hypodorian mode, literally meaning below dorian, is a musical mode or diatonic scale of ancient Greece that was based upon the dorian tetrachord: a series of rising intervals of a semitone followed by two whole tones. ...