/ Dictionary / Index P papain: Meaning and Definition of Find definitions for: pa•pa•in Pronunciation: (pu-pā'in, -pī'in), [key] — n. a proteolytic enzyme found in the fruit of the papaya tree, Carica papaya. a commercial preparation of this used as a meat tenderizer and in medicine as a digestant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: papain (Thesaurus) Papago papal Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language