SEMITONE
semitone, half step
(noun) the musical interval between adjacent keys on a keyboard instrument
Source: WordNet® 3.1
Etymology
Noun
semitone (plural semitones)
(music) The musical interval equal (exactly or approximately) to half a tone or one-twelfth of an octave
(music) Any of the pitches of the chromatic scale
Synonyms
• half-step
Anagrams
• monetise, one-times
Source: Wiktionary
Sem"i*tone, n. Etym: [Pref. semi- + tone. CF. Hemitone.] (Mus.)
Definition: Half a tone; -- the name commonly applied to the smaller
intervals of the diatonic scale.
Note: There is an impropriety in the use of this word, and half step
is now preferred. See Tone. J. S. Dwight.
Source: Webster’s Unabridged Dictionary 1913 Edition