Oxford Dictionary English semitone noun noun BrE BrE//ˈsemitəʊn// ; NAmE NAmE//ˈsemitoʊn// (British English) (North American English half step, halftone) (music) Add to my wordlistjump to other results half a tone on a musical scale, for example the interval between C and C♯ or between E and F compare stepCheck pronunciation: semitone oxfordlearnersdictionaries.com