/ Dictionary / Index F formula weight: Meaning and Definition of Find definitions for: for'mula weight" Pronunciation: [key] — Chem. Chem. (of a molecule) See (of an ionic compound that does not form molecules) the sum of the atomic weights of the atoms of the formula unit. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. formula unit formulism Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language