/ Dictionary / Index L lighthouse tube: Meaning and Definition of Find definitions for: light'house tube" Pronunciation: [key] — Electronics. Electronics. a vacuum tube with the electrodes arranged in parallel layers closely spaced, giving a relatively high-power output at high frequencies. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Lighthouse Point Light in August* Related Content Daily Word Quiz: effervescent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language