/ Dictionary / Index R radiothon: Meaning and Definition of Find definitions for: ra•di•o•thon Pronunciation: (rā'dē-ō-thon"), [key] — n. an on-the-air radio campaign, often lasting 24 hours or more, designed to raise money for a radio station, charity, the arts, etc., as from listeners phoning in and pledging specific donations, sometimes in exchange for gifts or premiums. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. radiothermy radiothorium Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language