Circle

noun
1.
a closed plane curve consisting of all points at a given distance from a point within it called the center. Equation: x 2 + y 2 = r 2 .
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.
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.
Government. an administrative division, especially of a province.
13.
Geography. a parallel of latitude.
14.
Astronomy.

(formerly) the orbit of a heavenly body.
meridian circle.

15.
Surveying. 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), circled, circling.
18.
to enclose in a circle; surround; encircle:
Circle the correct answer on the exam paper. The enemy circled the hill.
19.
to move in a circle or circuit around; rotate or revolve around:
He circled the house cautiously.
20.
to change course so as to pass by or avoid collision with; bypass; evade:
The ship carefully circled the iceberg.
verb (used without object), circled, circling.
21.
to move in a circle or circuit:
The plane circled for half an hour before landing.
22.
Movies, Television. to iris (usually followed by in or out).
Idioms
23.
circle the wagons,

(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.
Slang. to prepare for an all-out, unaided defensive fight:
The company has circled the wagons since its market share began to decline.

noun
1.
(maths) a closed plane curve every point of which is equidistant from a given fixed point, the centre. Equation: (x –h)² + (y –k)² = r² where r is the radius and (h, k) are the coordinates of the centre; area πr²; circumference: 2πr
2.
the figure enclosed by such a curve
3.
(theatre) the section of seats above the main level of the auditorium, usually comprising the dress circle and the upper circle
4.
something formed or arranged in the shape of a circle
5.
a group of people sharing an interest, activity, upbringing, etc; set: golf circles, a family circle
6.
a domain or area of activity, interest, or influence
7.
a circuit
8.
a process or chain of events or parts that forms a connected whole; cycle
9.
a parallel of latitude See also great circle, small circle
10.
the ring of a circus
11.
one of a number of Neolithic or Bronze Age rings of standing stones, such as Stonehenge, found in Europe and thought to be associated with some form of ritual or astronomical measurement
12.
(hockey) See striking circle
13.
a circular argument See vicious circle (sense 2)
14.
come full circle, to arrive back at one’s starting point See also vicious circle
15.
go round in circles, run round in circles, to engage in energetic but fruitless activity
verb
16.
to move in a circle (around): we circled the city by car
17.
(transitive) to enclose in a circle; encircle

circle cir·cle (sûr’kəl)
n.

A ring-shaped structure or group of structures.

A line or process with every point equidistant from the center.

circle
(sûr’kəl)

A closed curve whose points are all on the same plane and at the same distance from a fixed point (the center).
see:

full circle
go around (in circles)
run around (in circles)
run rings (circles) around
vicious circle