/ Dictionary / Index S sodium polysulfide: Meaning and Definition of Find definitions for: so'dium polysul'fide Pronunciation: [key] — Chem. Chem. a yellow-brown, water-soluble, granular powder, NaS, used chiefly in the manufacture of sulfur dyes, insecticides, and synthetic rubber. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sodium phosphate sodium propionate Related Content Daily Word Quiz: illegible Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language