/ Dictionary / Index T tumor necrosis factor: Meaning and Definition of Find definitions for: tu'mor necro"sis fac"tor Pronunciation: [key] a protein, produced in humans and other animals, that is destructive to cells showing abnormally rapid growth: identical with cachectin. Abbr.: TNF Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tumorigenic tump Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language