/ Dictionary / Index D dimethyl sulfate: Meaning and Definition of Find definitions for: dimeth'yl sul'fate Pronunciation: [key] — Chem. Chem. a colorless or yellow, slightly water-soluble, poisonous liquid, (CH)SO, used chiefly in organic synthesis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dimethylnitrosamine dimethyl sulfoxide Related Content Daily Word Quiz: labyrinth Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language