tone
An interval of two semitones, also called a whole step.
In Depth
A tone (also called a whole step or whole tone) is an interval of two semitones — the distance from C to D, or from F♯ to G♯. Major and minor scales are built from specific patterns of tones and semitones, making the tone one of the two basic building blocks of Western pitch organisation.
The word tone has several additional meanings in music. It can refer to the quality of a sound (a warm tone, a harsh tone), a single musical sound (a sustained tone), or the overall character of a piece. The whole-tone scale, built entirely of tones with no semitones, was used by Debussy to create a dreamlike, floating harmonic quality with no sense of direction or resolution.
The tone of a Stradivarius violin has been studied by physicists, chemists, and wood scientists for centuries. Some attribute it to the wood, others to the varnish, and no modern maker has definitively cracked the secret.