Editing Semitone (section)

{{About|the musical interval|the printing method|Halftone}}
{{Infobox Interval| 
       main_interval_name = semitone|
       inverse=[[major seventh]] (for minor second); [[diminished octave]] (for augmented unison); [[augmented octave]] (for diminished unison)|
       complement=[[major seventh]]|
       other_names = minor second,<br />diatonic semitone,<br />augmented unison,<br />diminished unison,<br />chromatic semitone|
       abbreviation = m2; A1 |
       semitones = 1 |
       interval_class = 1 |
       just_interval = 16:15,<ref name="Duffin">{{cite book|last1=Duffin|first1=Ross W.|title=How equal temperament ruined harmony : (and why you should care)|date=2008|publisher=W. W. Norton|location=New York|isbn=978-0-393-33420-3|page=163|edition=First published as a Norton paperback.|url=https://books.google.com/books?id=i5LC7Csnw7UC&q=how+equal+temperament+ruined+harmony|access-date=28 June 2017}}</ref> 17:16,<ref name="Haluska">Haluska, Jan (2003). ''The Mathematical Theory of Tone Systems'', p. xxiv. {{ISBN|0-8247-4714-3}}. Overtone semitone.</ref> 27:25, 135:128,<ref name="Duffin" /> 25:24,<ref name="Duffin" /> 256:243|
       cents_equal_temperament = 100<ref name="Duffin" />|
       cents_24T_equal_temperament = |
       cents_just_intonation = 112,<ref name="Duffin" /> 105, 133, 92,<ref name="Duffin" /> 71,<ref name="Duffin" /> 90
}}
[[File:Minor second on C.png|thumb|Minor second[[File:Minor second on C.mid]]]]

A '''semitone''', also called a '''minor second''', '''half step''', or a '''half tone''',<ref>''Semitone'', ''half step'', ''half tone'', ''halftone'', and ''half-tone'' are all variously used in sources.[http://www.merriam-webster.com/dictionary/half+step][http://www.merriam-webster.com/dictionary/half%20tone][http://dictionary.reference.com/browse/half%20tone][https://books.google.com/books?id=sTMbuSQdqPMC&q=a+half+step+is+called+a+semitone&pg=PA19][https://books.google.com/books?id=iYgSJSxWW2sC]
<br />[[Aaron Copland]], [[Leonard Bernstein]], and others use "half tone".[https://books.google.com/books?id=dsyPycO3GfgC&q=the+twelve+chromatic+ones,+arranged+in+the+following+order:+two+whole+tones+followed+by+a+half+tone,+plus+three+whole+tones+followed+by+a+half+tone.&pg=PA41]
[https://books.google.com/books?id=d-zwOLoDIcEC&q=Now,+if+you+remember+that+the+step+from+any+note+on+the+piano+to+the+note+just+next+to+it,+whether+it%27s+black+or+white,+is+a+step+of+a+half+tone,+you+can+see+that+the+entire+piano+keyboard+is+made+up+of+only+half+tones,+one+after+another.&pg=PA185][https://books.google.com/books?id=PoM6AAAAMAAJ&q=almost+a+half-tone+sharp][https://books.google.com/books?id=1nSqLzjZBKwC&q=This+is+easy+on+the+guitar,+since+from+one+fret+to+the+next+is+a+half+tone+(also+called+half+step+or+semitone).&pg=PA116]
<br />One source says that ''step'' is "chiefly US",[https://web.archive.org/web/20060301170305/http://www.askoxford.com/concise_oed/step] and that ''half-tone'' is "chiefly N. Amer."[https://archive.today/20130117121046/http://www.askoxford.com/concise_oed/halftone]
</ref> is the smallest [[interval (music)|musical interval]] commonly used in Western tonal music,<ref>Miller, Michael. [https://books.google.com/books?id=sTMbuSQdqPMC ''The Complete Idiot's Guide to Music Theory, 2nd ed'']. [Indianapolis, Indiana]: Alpha, 2005. {{ISBN|1-59257-437-8}}. p. 19.</ref> and it is considered the most [[Consonance and dissonance#Dissonance|dissonant]]<ref>{{cite book | title = Sound: An Elementary Text-book for Schools and Colleges | first = John Walton |last = Capstick | publisher = Cambridge University Press | year = 1913 | url = https://books.google.com/books?id=bwNJAAAAIAAJ&q=most+dissonant-interval+semitone+intitle:sound&pg=PA227 }}</ref> when sounded harmonically.
It is defined as the interval between two adjacent notes in a [[chromatic scale|12-tone scale]] (or half of a [[whole step]]), visually seen on a keyboard as the distance between two keys that are adjacent to each other. For example, C is adjacent to C{{music|sharp}}; the interval between them is a semitone.<ref>{{Cite web |title=musictheory.net |url=https://www.musictheory.net/lessons/20 |access-date=2024-01-04 |website=www.musictheory.net}}</ref>

In a 12-note approximately equally divided scale, any interval can be defined in terms of an appropriate number of semitones (e.g. a [[whole tone]] or major second is 2 semitones wide, a [[major third]] 4 semitones, and a [[perfect fifth]] 7 semitones).

In [[music theory]], a distinction is made<ref name="Wharram">{{cite book | title=Elementary Rudiments of Music | edition=2nd| last=Wharram| first=Barbara| year=2010| page=17| publisher=Frederick Harris Music| location=Mississauga, Ontario| isbn=978-1-55440-283-0}}</ref> between a '''diatonic semitone''', or '''minor second''' (an interval encompassing two different [[staff position]]s, e.g. from C to D{{music|flat}}) and a '''chromatic semitone''' or '''augmented unison''' (an interval between two notes at the same staff position, e.g. from C to C{{music|sharp}}). These are [[Enharmonic|enharmonically equivalent]] if and only if [[Equal temperament|twelve-tone equal temperament]] is used; for example, they are not the same thing in [[meantone temperament]], where the diatonic semitone is distinguished from and larger than the chromatic semitone (augmented unison), or in [[Pythagorean tuning]], where the diatonic semitone is smaller instead. See {{slink|Interval (music)|Number}} for more details about this terminology.

In [[twelve-tone equal temperament]] all semitones are equal in size (100 cents). In other tuning systems, "semitone" refers to a family of intervals that may vary both in size and name. In [[Pythagorean tuning]], seven semitones out of twelve are diatonic, with ratio 256:243 or 90.2 cents ([[#Pythagorean tuning|Pythagorean limma]]), and the other five are chromatic, with ratio 2187:2048 or 113.7 cents ([[#Pythagorean tuning|Pythagorean apotome]]); they differ by the [[Pythagorean comma]] of ratio 531441:524288 or 23.5 cents. In [[quarter-comma meantone]], seven of them are diatonic, and 117.1 cents wide, while the other five are chromatic, and 76.0 cents wide; they differ by the lesser [[diesis]] of ratio 128:125 or 41.1 cents. 12-tone scales tuned in [[just intonation]] typically define three or four kinds of semitones. For instance, [[Five-limit tuning#Size of intervals|Asymmetric]] [[five-limit tuning]] yields chromatic semitones with ratios 25:24 (70.7 cents) and 135:128 (92.2 cents), and diatonic semitones with ratios 16:15 (111.7 cents) and 27:25 (133.2 cents). For further details, see [[Semitone#Just intonation|below]].

The condition of having semitones is called hemitonia; that of having no semitones is [[Anhemitonic scale|anhemitonia]]. A [[Scale (music)|musical scale]] or [[Chord (music)|chord]] containing semitones is called hemitonic; one without semitones is anhemitonic.