/ Dictionary / Index E extinguishant: Meaning and Definition of Find definitions for: ex•tin•guish•ant Pronunciation: (ik-sting'gwi-shunt), [key] — n. a substance used in extinguishing fires. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. extinguish extinguisher Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language