Definitions for "Semitones"
Keywords:  halfway, pitch, octave, piano, piston
The semitone is the smallest interval (or distance between pitches) that you can play on a piano keyboard; in equal temperment, each semitone equals exactly 100 cents. In Western harmony, an octave (for example, from C to C' ), can be divided into 12 semitones. valve, piston and rotary A valve is a mechanism which changes the length of the tube, or body of a wind instrument; it allows you to play a wider range of notes. A piston valve features a that moves up and down in a casing; a rotary valve changes the air passage by means of a rotor activated by a lever.
(half step, half tone) a pitch interval halfway between two whole tones.