/ Dictionary / Index I ignitron: Meaning and Definition of Find definitions for: ig•ni•tron Pronunciation: (ig-nī'tron, ig'ni-tron), [key] — n. Electronics. a cathode-arc vacuum tube with an auxiliary electrode projecting into a pool of mercury: it conducts current when the anode is positive. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ignition system ignoble Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language