/ Dictionary / Index E epact: Meaning and Definition of Find definitions for: e•pact Pronunciation: (ē'pakt), [key] — n. the difference in days between a solar year and a lunar year. the number of days since the new moon at the beginning of the calendar year, January 1. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. EPA epagoge Related Content Daily Word Quiz: loathe Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language