/ Dictionary / Index S sour gum: Meaning and Definition of Find definitions for: sour' gum" Pronunciation: [key] a tree, Nyssa sylvatica, of eastern North America, having elliptic leaves, dark-blue, berrylike fruit, and wood with a variety of commercial uses. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sour grapes sour mash Related Content Daily Word Quiz: ounterfeit Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language