<p><strong>Adjective</strong></p><ul><li>having the form of a circle; round: a circular tower.</li><li>of or relating to a circle: a circular plane.</li><li>moving in or forming a circle or a circuit: the circular rotation of the earth.</li><li>moving or occurring in a cycle or round: the circular succession of the seasons.</li><li>roundabout; indirect; circuitous: a circular route.</li><li>Logic. of or relating to reasoning in which the conclusion is ostensibly proved, but in actuality it or its equivalent has been assumed as a premise.</li><li>pertaining to a circle or set of persons.</li><li>(of a letter, memorandum, etc.) addressed to a number of persons or intended for general circulation.</li></ul><p><strong>Noun</strong></p><ul><li>Also circ[+].</li><li>a letter, advertisement, notice, or statement for circulation among the general public.</li></ul>