/ Dictionary / Index E equivalence class: Meaning and Definition of Find definitions for: equiv'alence class" Pronunciation: [key] — Math. Math. the set of elements associated by an equivalence relation with a given element of a set. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. equivalence equivalence principle Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language