Diatonic (adjective)

1. Relating to the use of the seven natural notes of a musical scale, as opposed to the use of chromatic notes.
2. Relating to music composed using the diatonic scale.

Origin:

From the greek prefix "dia-" meaning "through" and the greek word "tonos" meaning "tone".

Examples:

1. The melody is diatonic, it only uses the seven notes of the major scale.
2. The song is diatonic, with no accidentals.
3. The diatonic scale is a seven-note scale in which the fifth and octave are both perfect.
4. The piece of music is diatonic, it is not using any chromatic notes.
5. The diatonic harmony is the basis of Western music.