/ Dictionary / Index P philtrum: Meaning and Definition of Find definitions for: phil•trum Pronunciation: (fil'trum), [key] — pl. -tra the vertical groove on the surface of the upper lip, below the septum of the nose. a philter. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. philtre -phily Related Content Daily Word Quiz: frugal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language