/ Dictionary / Index S sicko: Meaning and Definition of Find definitions for: sick•o Pronunciation: (sik'ō), [key] — pl. sick•os. sickie (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sickness sickout 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