Pronunciation: (sûr'kyu-lur),[key] —adj. 1. having the form of a circle; round: a circular tower. 2. of or pertaining to a circle: a circular plane. 3. moving in or forming a circle or a circuit: the circular rotation of the earth. 4. moving or occurring in a cycle or round: the circular succession of the seasons. 5. roundabout; indirect; circuitous: a circular route. 6. Logic.of or pertaining to reasoning in which the conclusion is ostensibly proved, but in actuality it or its equivalent has been assumed as a premise.
7. pertaining to a circle or set of persons.
8. (of a letter, memorandum, etc.) addressed to a number of persons or intended for general circulation.
—n. a letter, advertisement, notice, or statement for circulation among the general public.