/ Dictionary / Index G grex: Meaning and Definition of Find definitions for: grex Pronunciation: (greks), [key] — n. a numerical system for measuring the size of fibers, filaments, or yarns, based on the weight in grams of 10,000 meters of the fibrous material. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. grewsome grey 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