semitone

[sem-ee-tohn, sem-ahy-] /ˈsɛm iˌtoʊn, ˈsɛm aɪ-/
noun, Music.
1.
a pitch interval halfway between two whole tones.
Also called half step, half tone.
Origin
1600-10; semi- + tone
Related forms
semitonic
[sem-ee-ton-ik, sem-ahy-] /ˌsɛm iˈtɒn ɪk, ˌsɛm aɪ-/ (Show IPA),
semitonal
[sem-ee-tohn-l, sem-ahy-] /ˌsɛm iˈtoʊn l, ˌsɛm aɪ-/ (Show IPA),
adjective
semitonally, adverb
British Dictionary definitions for semitone

semitone

/ˈsɛmɪˌtəʊn/
noun
1.
an interval corresponding to a frequency difference of 100 cents as measured in the system of equal temperament, and denoting the pitch difference between certain adjacent degrees of the diatonic scale (diatonic semitone) or between one note and its sharpened or flattened equivalent (chromatic semitone); minor second Also called (US and Canadian) half step Compare whole tone
Derived Forms
semitonic (ˌsɛmɪˈtɒnɪk) adjective
semitonally, adverb
Word Origin and History for semitone
n.

c.1600, from semi- + tone (n.) in the musical sense.