1922, verbal noun from broadcast (v.).
Broadcasting, as distinct from wireless communication, may be said to have come into being about 1920. It may be defined as the systematic diffusion, by radio telephony, of music, lectures, drama, humour, news and information bulletins, speeches and ceremonies, pictures and other matter susceptible of appreciation by a scattered audience, individually or in groups, with appropriate receiving apparatus. [Encyclopedia Britannica, 1929]
broad
broadband
broad-brim
broadcast
broadcaster
broadcasting
broadcloth
broaden
broad-minded
broadsheet
broadside