/dim'euh nooh"sheuhn, -nyooh"-/ , n.
1. the act, fact, or process of diminishing; lessening; reduction.
2. Music. the repetition or imitation of a subject or theme in notes of shorter duration than those first used.
[ 1275-1325; ME diminucion diminuciun diminution- (s. of diminutio ), for deminution- (s. of deminutio ) (by influence of dimunuere; see DIMINISH), equiv. to deminut ( us ) (ptp. of deminuere, equiv. to de- DE- + minuere to lessen) + -ion- -ION ]