/ Dictionary / Index S supertax: Meaning and Definition of Find definitions for: su•per•tax Pronunciation: (s'pur-taks"), [key] — n. a tax in addition to a normal tax, as one upon income above a certain amount. a surtax. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: supertax (Thesaurus) supertask supertitle Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language