/ Dictionary / Index C cisco: Meaning and Definition of Find definitions for: cis•co Pronunciation: (sis'kō), [key] — pl. -co, -coes, -cos. any of several whitefishes of the genus Coregonus, of the Great Lakes and smaller lakes of eastern North America. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: cisco (Thesaurus) Ciscaucasia ciseaux 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