/ Dictionary / Index E ecesis: Meaning and Definition of Find definitions for: e•ce•sis Pronunciation: (i-sē'sis), [key] — n. Ecol. the establishment of an immigrant plant in a new environment. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ecesis (Thesaurus) ecdysone Ecevit Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language