Pitch circle

Pitch circle
Circle Cir"cle (s[~e]r"k'l), n. [OE. cercle, F. cercle, fr. L. circulus (Whence also AS. circul), dim. of circus circle, akin to Gr. kri`kos, ki`rkos, circle, ring. Cf. {Circus}, {Circum-}.] [1913 Webster] 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. [1913 Webster]

2. The line that bounds such a figure; a circumference; a ring. [1913 Webster]

3. (Astron.) An instrument of observation, the graduated limb of which consists of an entire circle. [1913 Webster]

Note: 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 circle} 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}. [1913 Webster]

4. A round body; a sphere; an orb. [1913 Webster]

It is he that sitteth upon the circle of the earth. --Is. xi. 22. [1913 Webster]

5. Compass; circuit; inclosure. [1913 Webster]

In the circle of this forest. --Shak. [1913 Webster]

6. 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. [1913 Webster]

As his name gradually became known, the circle of his acquaintance widened. --Macaulay. [1913 Webster]

7. A circular group of persons; a ring. [1913 Webster]

8. A series ending where it begins, and repeating itself. [1913 Webster]

Thus in a circle runs the peasant's pain. --Dryden. [1913 Webster]

9. (Logic) A form of argument in which two or more unproved statements are used to prove each other; inconclusive reasoning. [1913 Webster]

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. [1913 Webster]

10. Indirect form of words; circumlocution. [R.] [1913 Webster]

Has he given the lie, In circle, or oblique, or semicircle. --J. Fletcher. [1913 Webster]

11. A territorial division or district. [1913 Webster]


{The Circles of the Holy Roman Empire}, ten in number, were those principalities or provinces which had seats in the German Diet. [1913 Webster]

{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 circuit} or {Voltaic circle}. See under {Circuit}.

{To square the circle}. See under {Square}.

Syn: Ring; circlet; compass; circuit; inclosure. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Pitch circle — Pitch Pitch, n. 1. A throw; a toss; a cast, as of something from the hand; as, a good pitch in quoits. [1913 Webster] {Pitch and toss}, a game played by tossing up a coin, and calling Heads or tails; hence: {To play pitch and toss with… …   The Collaborative International Dictionary of English

  • pitch circle — n. an imaginary circle that intersects the teeth of a gear at the actual points where the teeth mesh with another gear: the pitch circles of two enmeshed gears are tangent …   English World dictionary

  • Pitch circle — In mechanical engineering, a pitch circle (operating) is the curve of intersection of a pitch surface of revolution and a plane of rotation. It is the imaginary circle that rolls without slipping with a pitch circle of a mating gear.1 Notes 1.… …   Wikipedia

  • pitch circle — noun Etymology: pitch (IV) : a pitch line in a circular gear that forms a circle concentric with the axis of the gear …   Useful english dictionary

  • pitch circle — Mach. an imaginary circle within the profiles of the teeth of a gear, such that it rotates against a similar circle rotating at the same rate on a meshing gear. Also called pitch line. [1810 20] * * * …   Universalium

  • pitch circle — noun Mechanics an imaginary circle concentric to a toothed wheel, along which the pitch of the teeth is measured …   English new terms dictionary

  • pitch circle — /ˈpɪtʃ sɜkəl/ (say pich serkuhl) noun an imaginary circle concentric with the axis of a toothed wheel, at such a distance from the base of the teeth that it is in contact with and rolls upon a similar circle of another toothed wheel engaging with …   Australian English dictionary

  • pitch circle — (PC) the circumference on which the centers of the wheel bolt holes are located …   Dictionary of automotive terms

  • pitch circle diameter — (PCD) The diameter of the stud holes/bolt holes for fixing the wheel to the hub. The pitch circle (PC) is usually shown as a double number, e.g., 5 5.5. The first number indicates the number of holes, and the second, the diameter of the PC …   Dictionary of automotive terms

  • Standard pitch circle — The circle which intersects the involute at the point where the pressure angle is equal to the profile angle of the basic rack.1 Notes 1. ANSI/AGMA 1012 G05 , Gear Nomenclature, Definition of Terms with Symbols …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”