The semitone (minor second) is the smallest distance between two pitches in twelve-tone equal temperament. On the piano it is any two adjacent keys (white-black, or white-white at E–F and B–C). Twelve semitones make a full octave.
A semitone can be diatonic (between different scale degrees, e.g. E–F) or chromatic (between the same degree with an accidental, C–C♯). Motion by semitone creates the sharpest pull: the leading tone that yearns to resolve into the tonic lies a semitone below it. In Ukrainian folk song, expressive semitone “sighs” give the melody a poignant, lyrical colouring. Learning to hear the semitone is the first step for every musician.
