circular vs circulate

circular is a noun but circulate is not a noun.

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

circular (noun)	circulate (noun)
an advertisement (usually printed on a page or in a leaflet) intended for wide distribution

circular (adjective)	circulate (adjective)
having the shape or form of a circle
describing a circle; moving in a circle

circular (verb)	circulate (verb)
	cause to become widely known
	become widely known and passed on
	move around freely from person to person or from place to place
	move through a space, circuit or system, returning to the starting point
	cause to be distributed
	cause to move in a circuit or system