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, especially when perpetually repeated; cycle: the circle of the year.
9. 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. an administrative division, especially of a province.
13. a parallel of latitude.
14. meridian circle
15. 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.
verb (used with object)
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.
verb (used without object)
1. to move in a circle or circuit: The plane circled for half an hour before landing.
2. to iris (usually followed by in or out).
1. Slang..to prepare for an all-out, unaided defensive fight: The company has circled the wagons since its market share began to decline.