Definitions
from The American Heritage® Dictionary of the English Language, 4th Edition
 n. A plane curve everywhere equidistant from a given fixed point, the center.
 n. A planar region bounded by a circle.
 n. Something, such as a ring, shaped like such a plane curve.
 n. A circular course, circuit, or orbit: a satellite's circle around the earth.
 n. A traffic circle.
 n. A curved section or tier of seats in a theater.
 n. A series or process that finishes at its starting point or continuously repeats itself; a cycle.
 n. A group of people sharing an interest, activity, or achievement: wellknown in artistic circles.
 n. A territorial or administrative division, especially of a province, in some European countries.
 n. A sphere of influence or interest; domain.
 n. Logic A vicious circle.
 transitive v. To make or form a circle around; enclose. See Synonyms at surround.
 transitive v. To move in a circle around.
 intransitive v. To move in a circle. See Synonyms at turn.
 idiom circle the wagons To take a defensive position; become defensive.
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. A twodimensional geometric figure, a line, consisting of the set of all those points in a plane that are equally distant from another point.
 n. A twodimensional geometric figure, a disk, consisting of the set of all those points of a plane at a distance less than or equal to a fixed distance from another point.
 n. Any thin threedimensional equivalent of the geometric figures.
 n. A curve that more or less forms part or all of a circle.
 n. Orbit.
 n. A specific group of persons.
 n. A line comprising two semicircles of 30 yards radius centred on the wickets joined by straight lines parallel to the pitch used to enforce field restrictions in a oneday match.
 n. A ritual circle that is casted three times deosil and closes three times widdershins either in the air with a wand or literally with stones or other itmes used for worship.
 n. A traffic circle or roundabout.
 v. To travel around along a curved path.
 v. To surround.
 v. To place or mark a circle around.
 v. To travel in circles.
from the GNU version of the Collaborative International Dictionary of English
 n. A plane figure, bounded by a single curve line called its circumference, every part of which is equally distant from a point within it, called the center.
 n. The line that bounds such a figure; a circumference; a ring.
 n. An instrument of observation, the graduated limb of which consists of an entire circle.
 n. A round body; a sphere; an orb.
 n. Compass; circuit; inclosure.
 n. A company assembled, or conceived to assemble, about a central point of interest, or bound by a common tie; a class or division of society; a coterie; a set.
 n. A circular group of persons; a ring.
 n. A series ending where it begins, and repeating itself.
 n. A form of argument in which two or more unproved statements are used to prove each other; inconclusive reasoning.
 n. Indirect form of words; circumlocution.
 n. A territorial division or district.
 intransitive v. To move circularly; to form a circle; to circulate.
 transitive v. To move around; to revolve around.
 transitive v. To encompass, as by a circle; to surround; to inclose; to encircle.
from The Century Dictionary and Cyclopedia
 To encircle; encompass; surround; inclose.
 To move around; revolve around.
 To make to move in a circle or to revolve.
 To move in a round or circle; circulate; revolve or turn circularly.
 To form a circle; assume or have the form of a circle.
 n. In elementary geom., a plane figure whose periphery is everywhere equally distant from a point within it, the center; in modern geom., the periphery of such a figure; a circumference.
 n. A circular formation or arrangement; a circlet; a ring: as, a circle of stones or of lights.
 n. A round body; a sphere; an orb.
 n. Circuit; course.
 n. Compass; inclosure.
 n. Something conceived as analogous to a circle; specifically, a number of persons intimately related to a central interest, person, or event; hence, a number of persons associated by any tie; a coterie; a set: as, a circle of ideas; to move in the higher circles of society; the circles of fashion; the family circle.
 n. A series ending where it begins, and perpetually repeated.
 n. A complete system, involving several subordinate divisions: as, the circle of the sciences.
 n. Circumlocution; indirect form of speech.
 n. In logic, an inconclusive form of argument, in which two or more unproved statements, or their equivalents, are used to prove each other: often called a vicious circle, or argument in a circle.
 n. The English equivalent of the name given in some countries, as in Germany, to certain administrative divisions.
 n. In astronomy and geodesy, a piece of metal or glass with lines engraved upon it so as to form graduations dividing the circumference of a circle into equal parts; hence, any instrument of which such a graduated circle forms the part that is most important or most difficult to make.
 n. A small shuttle made in the form of a horseshoe, and moving in a circular path.
 n. In geography, a small circle the plane of which is perpendicular to the axis of the earth; a circle of the globe parallel to the equator: more usually called a parallel of latitude.
 n. A line showing the hour on a sundial.
 n. A circle of declination: referred to as the twohour circle, etc., especially as the sixhour circle.
 n. A bookbinders' wheelshaped tool, having a design engraved on the rim or edge.
 n. A circle of communicating arterioles on the sclerotic surrounding the optic nerve.
 n. A ring of fibrocartilage which gives support to the auriculoventricular valve on each side of the heart. Also called circulus callosus Halleri.
 n. The circumcircle of the triangle of similitude of three figures directly similar.
 n. Second Lemoine circle. Same as cosine circle.
 n. In gearing, the pitchcircle.
 n. In surgery, the passage of chyme, after gastroenterostomy, through the artificial opening into the intestine, and then its regurgitation, in consequence of antiperistaltic action, through the pylorus back into the stomach.
 n. The mutually accelerating action of two independent but coexisting diseases.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
 v. travel around something
 n. movement once around a course
 n. a road junction at which traffic streams circularly around a central island
 n. street names for flunitrazepan
 v. move in circles
 n. an unofficial association of people or groups
 v. form a circle around
 n. any circular or rotating mechanism
 n. ellipse in which the two axes are of equal length; a plane curve generated by one point moving at a constant distance from a fixed point
 n. something approximating the shape of a circle
 n. a curved section or tier of seats in a hall or theater or opera house; usually the first tier above the orchestra
Etymologies
from The American Heritage® Dictionary of the English Language, 4th Edition
from Wiktionary, Creative Commons Attribution/ShareAlike License
Examples

_ A circle whose center moves around _upon_, or in, the circumference of another _circle_; as the orbit of the moon in its motion with the earth around the sun.
Orthography As Outlined in the State Course of Study for Illinois

(STANDISH _places the chairs above and below the table in the circle, then the chair on the_ R. _side of the fireplace in the circle_.)

(_Goes inside circle and sits down up_ C. _in circle_.)

The main circle is bidirectional and each entrance has it's own unidirectional mini circle.

We need not imagine that Aristides meant the word circle literally.

And in particular he singled out for comment the following question, which was one of those set, “Using the term circle as extending to the case where the radius is a pure imaginary, it is required to construct the common chord of two given circles.”

My brother has relayed his circle is the same ... few hunt squirrels, and those that once did have put it to the side for deer, turkey, etc.

This circle is a foundation for each of our lives.

I stay within what I call my circle of competence.

I think the circle is a fine form as well especially since clothes will fill any space.
MaryW commented on the word circle
Matthew T. Bodie, Holacracy and the Law, 42 Del. J. Corp. L. 62122 (2018) (footnotes omitted)October 22, 2018
bilby commented on the word circle
"a round straight line with a hole in the middle."
 anon.
September 9, 2008
treeseed commented on the word circle
a town in Alaska, USA
February 26, 2008
slumry commented on the word circle
a small ring
June 19, 2007