broadcast vs simulcast

broadcast and simulcast both are nouns.

Word	Noun	Adjective	Verb	Adverb
broadcast	Yes	No	Yes	No
simulcast	Yes	No	No	No

As nouns, simulcast is a hyponym of broadcast; that is, simulcast is a word with a more specific, narrower meaning than broadcast:

broadcast: message that is transmitted by radio or television
simulcast: a broadcast that is carried simultaneously by radio and television (or by FM and AM radio)

Other hyponyms of broadcast include rebroadcast, radio broadcast, telecast, newscast.

broadcast (noun)	simulcast (noun)
message that is transmitted by radio or television	a broadcast that is carried simultaneously by radio and television (or by FM and AM radio)
a radio or television show

broadcast (verb)	simulcast (verb)
cause to become widely known
broadcast over the airwaves, as in radio or television
sow over a wide area, especially by hand