ETYM Latin diminutio, or perh. rather deminutio: cf. French diminution. Related to Diminish.
1. The act of diminishing, or of making or becoming less; state of being diminished; reduction in size, quantity, or degree; -- opposed to augmentation or increase.
2. The act of lessening dignity or consideration, or the state of being deprived of dignity; a lowering in estimation; degradation; abasement.
In music, a reduction of interval size, of chord, loudness level, or note values of a theme.