Noun

• S: (n) circular, handbill, bill, broadside, broadsheet, flier, flyer, throwaway (an advertisement (usually printed on a page or in a leaflet) intended for wide distribution) "he mailed the circular to all subscribers"

Adjective

• S: (adj) round, circular (having the shape or form of a circle)
• S: (adj) circular, rotary, orbitual (describing a circle; moving in a circle) "the circular motion of the wheel"