/ Dictionary / Index S sign-up: Meaning and Definition of Find definitions for: sign-up Pronunciation: (sīn'up"), [key] — n. an act or instance of signing up. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sign-up (Thesaurus) signpost Signy Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language