/ Dictionary / Index S semitone: Meaning and Definition of Find definitions for: sem•i•tone Pronunciation: (sem'ē-tōn", sem'ī-), [key] — n. Music. a pitch interval halfway between two whole tones. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: semitone (Thesaurus) Semitist semitrailer Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language