/ Dictionary / Index I instillator: Meaning and Definition of Find definitions for: in•stil•la•tor Pronunciation: (in'stu-lā"tur), [key] — n. Med. an apparatus for putting liquid drop by drop into a cavity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: instillator (Thesaurus) instillation instinct Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language