/ Dictionary / Index C cistron: Meaning and Definition of Find definitions for: cis•tron Pronunciation: (sis'tron), [key] — n. Genetics. a segment of DNA that encodes for the formation of a specific polypeptide chain; a structural gene. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: cistron (Thesaurus) cistern barometer cistvaen Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language