/ Dictionary / Index P photoelectric tube: Meaning and Definition of Find definitions for: pho'toelec'tric tube' Pronunciation: [key] — Electronics. Electronics. phototube. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photoelectric threshold photoelectron Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language