/ Dictionary / Index D dimin.: Meaning and Definition of Find definitions for: dimin. Pronunciation: [key] diminish. diminuendo. diminutive. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dimetrodon diminish Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language