/ Dictionary / Index E ESR: Meaning and Definition of Find definitions for: ESR Pronunciation: [key] erythrocyte sedimentation rate: the rate at which red blood cells settle in a column of blood, serving as a diagnostic test. electron spin resonance. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: esr (Thesaurus) esquire esrog Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language