1767, "dispersed upon the ground by hand," in reference to seed, from broad (adj.) + past participle of cast (v.). Figurative sense "widely spread" is recorded by 1785. As an adverb from 1832. 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.