In geometry, a plane figure comprehended by a single curve line, called its circumference, every part of which is equally distant from a point called the center. Of course all lines drawn from the center to the circumference or periphery, are equal to each other.

In popular use, the line that comprehends the figure, the plane or surface comprehended, and the whole body or solid matter of a round substance, are denominated a circle; a ring; an orb; the earth.

Compass; circuit; as the circle of the forest.

An assembly surrounding the principal person. Hence, any company, or assembly; as a circle of friends, or of beauties. Hence the word came to signify indefinitely a number of persons of a particular character, whether associated or not; as a political circle; the circle of ones acquaintance; having however reference to a primary association.

A series ending where it begins, and perpetually repeated; a going round. Thus in a circle runs the peasants pain.

Circumlocution; indirect form of words.

In logic, an inconclusive form of argument, when the same terms are proved in orbem by the same terms, and the parts of the syllogism alternately by each other, directly and indirectly; or when the foregoing proposition is proved by the following, and the following is inferred from the foregoing; as, that heavy bodies descend by gravity, and that gravity is a quality by which a heavy body descends.

Circles of the sphere, are such as cut the mundane sphere, and have their periphery either on its movable surface, as the meridians; or in another immovable, conterminous and equidistant surface, as the ecliptic, equator, and its parallels.

Circles of altitude or almucantars, are circles parallel to the horizon, having their common pole in the zenith, and diminishing as they approach the zenith.

Circles of latitude, are great circles perpendicular to the plane of the ecliptic, passing through its poles and through every star and planet.

Circles of longitude, are lesser circles parallel to the ecliptic, diminishing as they recede from it.

Circle of perpetual apparition, one of the lesser circles, parallel to the equator, described by any point of the sphere touching the northern point of the horizon, and carried about with the diurnal motion. The stars within this circle never set.

Circle of perpetual occultation, another lesser circle at a like distance from the equator, which includes all the stars which never appear in our hemisphere.

Diurnal circles, are immovable circles supposed to be described by the several stars and other points in the heavens, in their diurnal rotation round the earth, or rather in the rotation of the earth round its axis.

Horary circles, in dialing, are the lines which show the hours on dials.

Circles of the empire, the provinces or principalities of the German empire, which have a right to be present at the diets. Maximilian I. divided the empire into six circles at first, and afterwards into ten; Austria, Burgundy, Lower Rhine, Bavaria, Upper Saxony, Franconia, Swabia, Upper Rhine, Westphalia, and Lower Saxony.

Druidical circles, in British Topography, are certain ancient inclosures formed by rude stones circularly arranged; as Stone- henge near Salisbury.

To move round; to revolve round. And other planets circle other suns.

To encircle; to encompass; to surround; to inclose.

To circle in, to confine; to keep together.