/ Dictionary / Index P pliotron: Meaning and Definition of Find definitions for: pli•o•tron Pronunciation: (plī'u-tron"), [key] — n. Electronics. any hot-cathode vacuum tube having an anode and one or more grids. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Pliofilm plique-à-jour Related Content Daily Word Quiz: laudable Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language