/ Dictionary / Index P prot-: Meaning and Definition of Find definitions for: prot- Pronunciation: [key] var. ofbefore a vowel: protamine. Prot. Pronunciation: [key] Protestant. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prosyllogism protactinium Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language