/ Dictionary / Index A A supply: Meaning and Definition of Find definitions for: A supply Pronunciation: [key] — Electronics. Electronics. a battery or other source of power for heating the filament or cathode heater of an electron tube. Cf. B supply, C supply. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. asunder Asur Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language