Nouns

(n)circular, handbill, bill, broadside, broadsheet, flier, flyer, throwawayan advertisement (usually printed on a page or in a leaflet) intended for wide distribution“he mailed the circular to all subscribers”

Adjectives

(a)round, circularhaving the shape or form of a circle
(s)circular, rotary, orbitaldescribing a circle; moving in a circle“the circular motion of the wheel”