/ Dictionary / Index E ecological niche: Meaning and Definition of Find definitions for: ec'olog'ical niche' Pronunciation: [key] niche (def. 3). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. E. coli* ecological succession Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language