"one who broadcasts," in any sense, 1922, agent noun from broadcast.
Entries linking to broadcaster
broadcast adj.
1767, "dispersed upon the ground by hand," in reference to seed, from broad (adj.) + past participle of cast (v.). The figurative sense of "widely spread" is recorded by 1785. As an adverb from 1832. The modern media use began with radio (1922, adjective and noun). As a verb, recorded from 1813 in an agricultural sense, 1829 in a figurative sense, 1921 in reference to radio.