/ Dictionary / Index S sit-upon: Meaning and Definition of Find definitions for: sit-up•on Pronunciation: (sit'u-pon", -pôn"), [key] — n. a piece of waterproof fabric or other material carried by campers, hikers, etc., and used for sitting on wet surfaces. the buttocks. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sit-up situs Related Content Daily Word Quiz: verdant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language