circulate vs broadcast

circulate is not a noun while broadcast is a noun.

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

As verbs, circulate and broadcast are synonyms defined as:

circulate (noun)	broadcast (noun)
	message that is transmitted by radio or television
	a radio or television show

circulate (verb)	broadcast (verb)
cause to become widely known	cause to become widely known
become widely known and passed on	broadcast over the airwaves, as in radio or television
move around freely from person to person or from place to place	sow over a wide area, especially by hand
move through a space, circuit or system, returning to the starting point
cause to be distributed
cause to move in a circuit or system