/ Dictionary / Index S SSS: Meaning and Definition of Find definitions for: SSS Pronunciation: [key] Selective Service System. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sss (Thesaurus) SSR SST Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language