Breadcrumb Home > 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: centrifugal Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language