CIRCLE, n.

1. 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.
2. 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. He that sitteth on the circle of the earth. Is. xl.
3. Compass; circuit; as, the circle of the forest. – Shak.
4. 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 one's acquaintance; having however reference to a primary association.
5. A series ending where it begins, and perpetually repeated; a going round. Thus in a circle runs the peasant's pain. – Dryden.
6. Circumlocution; indirect form of words. – Fletcher.
7. 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?” – Encyc. Glanville. Watts.
8. 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.
9. 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.
10. Circles of latitude, are great circles perpendicular to the plane of the ecliptic, passing through its poles and through every star and planet.
11. Circles of longitude; are lesser circles parallel to the ecliptic, diminishing as they recede from it.
12. 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.
13. 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.
14. 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.
15. Horary circles, in dialing, are the lines which show the hours on dials.
16. 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.
17. Druidical circles, in British topography, are certain ancient inclosures formed by rude stones circularly arranged; as Stonehenge near Salisbury. – Encyc.

To move circularly; as, the bowl circles; the circling years.

1. To move round; to revolve round. And other planets circle other suns. – Pope.
2. To encircle; to encompass; to surround; to inclose. – Prior. Pope.
3. To circle in, to confine; to keep together. – Digby.

1. 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.
2. To move around] to revolve around.
   
   

   Other planets circle other suns.
   Pope.

3. To move circularly; to form a circle; to circulate.
   
   

   Thy name shall circle round the gaping through.
   Byron.

4. The line that bounds such a figure; a circumference; a ring.
5. To encompass, as by a circle; to surround; to inclose; to encircle.
   
   
   Prior. Pope.

   Their heads are circled with a short turban.
   Dampier.

   So he lies, circled with evil.
   Coleridge.

   To circle in, to confine; to hem in; to keep together; as, to circle bodies in. Sir K. Digby.

6. An instrument of observation, the graduated limb of which consists of an entire circle.
   
   

   * When it is fixed to a wall in an observatory, it is called a mural circle; when mounted with a telescope on an axis and in Y's, in the plane of the meridian, a meridian or transit circle; when involving the principle of reflection, like the sextant, a reflecting circle; and when that of repeating an angle several times continuously along the graduated limb, a repeating circle.

7. A round body; a sphere; an orb.
   
   

   It is he that sitteth upon the circle of the earth.
   Is. xi. 22.

8. Compass; circuit; inclosure.
   
   

   In the circle of this forest.
   Shak.

9. 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.
   
   

   As his name gradually became known, the circle of his acquaintance widened.
   Macaulay.

10. A circular group of persons; a ring.
11. A series ending where it begins, and repeating itself.
    
    

    Thus in a circle runs the peasant's pain.
    Dryden.

12. A form of argument in which two or more unproved statements are used to prove each other; inconclusive reasoning.
    
    

    That heavy bodies descend by gravity; and, again, that gravity is a quality whereby a heavy body descends, is an impertinent circle and teaches nothing.
    Glanvill.

13. Indirect form of words; circumlocution.
    
    
    [R.]

    Has he given the lie,
    In circle, or oblique, or semicircle.
    J. Fletcher.

14. A territorial division or district.
    
    

    * The Circles of the Holy Roman Empire, ten in number, were those principalities or provinces which had seats in the German Diet.

    Azimuth circle. See under Azimuth. -- Circle of altitude (Astron.), a circle parallel to the horizon, having its pole in the zenith; an almucantar. -- Circle of curvature. See Osculating circle of a curve (Below). -- Circle of declination. See under Declination. -- Circle of latitude. (a) (Astron.) A great circle perpendicular to the plane of the ecliptic, passing through its poles. (b) (Spherical Projection) A small circle of the sphere whose plane is perpendicular to the axis. -- Circles of longitude, lesser circles parallel to the ecliptic, diminishing as they recede from it. -- Circle of perpetual apparition, at any given place, the boundary of that space around the elevated pole, within which the stars never set. Its distance from the pole is equal to the latitude of the place. -- Circle of perpetual occultation, at any given place, the boundary of the space around the depressed pole, within which the stars never rise. -- Circle of the sphere, a circle upon the surface of the sphere, called a great circle when its plane passes through the center of the sphere; in all other cases, a small circle. -- Diurnal circle. See under Diurnal. -- Dress circle, a gallery in a theater, generally the one containing the prominent and more expensive seats. -- Druidical circles (Eng. Antiq.), a popular name for certain ancient inclosures formed by rude stones circularly arranged, as at Stonehenge, near Salisbury. -- Family circle, a gallery in a theater, usually one containing inexpensive seats. -- Horary circles (Dialing), the lines on dials which show the hours. -- Osculating circle of a curve (Geom.), the circle which touches the curve at some point in the curve, and close to the point more nearly coincides with the curve than any other circle. This circle is used as a measure of the curvature of the curve at the point, and hence is called circle of curvature. -- Pitch circle. See under Pitch. -- Vertical circle, an azimuth circle. -- Voltaic circle or circuit. See under Circuit. -- To square the circle. See under Square.

    Syn. -- Ring; circlet; compass; circuit; inclosure.