/ Dictionary / Index F fatso: Meaning and Definition of Find definitions for: fat•so Pronunciation: (fat'sō), [key] — pl. -sos, -soes. a fat person (often used as a disparaging and offensive term of address). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fatso (Thesaurus) fatsia fat-soluble Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language