[ rey-dee-oh-thon ]
/ ˈreɪ di oʊˌθɒn /
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.
Origin of radiothon
1960–65, Americanism; radio + -thon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019