/ Dictionary / Index E episome: Meaning and Definition of Find definitions for: ep•i•some Pronunciation: (ep'u-sōm"), [key] — n. Genetics. bacterial DNA that is extrachromosomal and that may replicate autonomously as a plasmid or become incorporated into the chromosome and replicate with it. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: episome (Thesaurus) episodic epispastic Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language