—n. 1. a closed plane curve consisting of all points at a given distance from a point within it called the center. Equation: x2 + y2 = r2.
2. the portion of a plane bounded by such a curve.
3. any circular or ringlike object, formation, or arrangement: a circle of dancers. 4. a ring, circlet, or crown.
5. the ring of a circus.
6. a section of seats in a theater: dress circle. 7. the area within which something acts, exerts influence, etc.; realm; sphere: A politician has a wide circle of influence. 8. a series ending where it began, esp. when perpetually repeated; cycle: the circle of the year. 9. Logic.an argument ostensibly proving a conclusion but actually assuming the conclusion or its equivalent as a premise; vicious circle.
10. a complete series forming a connected whole; cycle: the circle of the sciences. 11. a number of persons bound by a common tie; coterie: a literary circle; a family circle. 12. Govt.an administrative division, esp. of a province.
13. Geog.a parallel of latitude.
14. Astron. a. (formerly) the orbit of a heavenly body.
b. See meridian circle. 15. Survey.a glass or metal disk mounted concentrically with the spindle of a theodolite or level and graduated so that the angle at which the alidade is set may be read.
16. a sphere or orb: the circle of the earth. 17. a ring of light in the sky; halo.
—v.t. 1. to enclose in a circle; surround; encircle: Circle the correct answer on the exam paper. The enemy circled the hill. 2. to move in a circle or circuit around; rotate or revolve around: He circled the house cautiously. 3. to change course so as to pass by or avoid collision with; bypass; evade: The ship carefully circled the iceberg. 4. circle the wagons, a. (in the early U.S. West) to form the wagons of a covered-wagon train into a circle for defensive purposes, as against Indian attack.
b. Slang.to prepare for an all-out, unaided defensive fight: The company has circled the wagons since its market share began to decline.
—v.i. 1. to move in a circle or circuit: The plane circled for half an hour before landing. 2. Motion Pictures,Television.to iris (usually fol. by in or out).