/ Dictionary / Index R responder: Meaning and Definition of Find definitions for: re•spond•er Pronunciation: (ri-spon'dur), [key] — n. a person or thing that responds. the part of a transponder that transmits the reply. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: responder (Thesaurus) respondent conditioning Responsa Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language