diatonic
/ˌdaɪəˈtɒnɪk/adjective
1- Music (of a scale, interval, etc.) involving only notes proper to the prevailing key without chromatic alteration【乐】（音阶、音程等）自然音阶的。
1.1
- (of a melody or harmony) constructed from such a scale（音调, 和声）自然音阶的。
词源
early 17th cent. （denoting a tetrachord divided into two tones and a lower semitone， or ancient Greek music based on this）： from French diatonique, or via late Latin from Greek diatonikos 'at intervals of a tone'， from dia 'through' + tonos 'tone'.