1767, adjective, in reference to the spreading of seed, from broad (adj.) + past participle of cast (v.). Figurative use is recorded from 1785. 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.
A transmission to multiple, unspecified recipients. On Ethernet, a broadcast packet is a special type of multicast packet which all nodes on the network are always willing to receive.