home r Rene Piirkop radio ra⋅di⋅o [rey-dee-oh] –noun 1. wireless telegraphy or telephony: speeches broadcast by radio. 2. an apparatus for receiving or transmitting radio broadcasts. 3. a message transmitted by radio. a b c d e f g h i j k l m n o p q r s t u v w x y z rack rain ray rainbow raze radio read reach record recumbent rabbit red-rev rat