/ Dictionary / Index E ephemerid: Meaning and Definition of Find definitions for: e•phem•er•id Pronunciation: (i-fem'ur-id), [key] — n. an insect of the order Ephemeroptera, comprising the mayflies. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ephemerid (Thesaurus) ephemerality ephemeris Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language