/ Dictionary / Index E extension agent: Meaning and Definition of Find definitions for: exten'sion a"gent Pronunciation: [key] an agent employed by the county government to work with farmers to increase crop yields, prevent erosion, eliminate blights or pests, and the like. Cf. county agent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. extension extension bolt Related Content Daily Word Quiz: supercilious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language