# Plane at infinity

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Plane at infinity
Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a like surface is a straight line; a surface without curvature. [1913 Webster]

2. (Astron.) An ideal surface, conceived as coinciding with, or containing, some designated astronomical line, circle, or other curve; as, the plane of an orbit; the plane of the ecliptic, or of the equator. [1913 Webster]

3. (Mech.) A block or plate having a perfectly flat surface, used as a standard of flatness; a surface plate. [1913 Webster]

4. (Joinery) A tool for smoothing boards or other surfaces of wood, for forming moldings, etc. It consists of a smooth-soled stock, usually of wood, from the under side or face of which projects slightly the steel cutting edge of a chisel, called the iron, which inclines backward, with an apperture in front for the escape of shavings; as, the jack plane; the smoothing plane; the molding plane, etc. [1913 Webster]

{Objective plane} (Surv.), the horizontal plane upon which the object which is to be delineated, or whose place is to be determined, is supposed to stand.

{Perspective plane}. See {Perspective}.

{Plane at infinity} (Geom.), a plane in which points infinitely distant are conceived as situated.

{Plane iron}, the cutting chisel of a joiner's plane.

{Plane of polarization}. (Opt.) See {Polarization}.

{Plane of projection}. (a) The plane on which the projection is made, corresponding to the perspective plane in perspective; -- called also principal plane. (b) (Descriptive Geom.) One of the planes to which points are referred for the purpose of determining their relative position in space.

{Plane of refraction} or {Plane of reflection} (Opt.), the plane in which lie both the incident ray and the refracted or reflected ray. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

### Look at other dictionaries:

• Plane at infinity — In projective geometry, the plane at infinity is a projective plane which is added to the affine 3 space in order to give it closure of incidence properties. The result of the addition is the projective 3 space, P^3 . If the affine 3 space is… …   Wikipedia

• plane at infinity — Etymology: plane (IV) : the aggregate of all points at infinity in projective geometry of three dimensions …   Useful english dictionary

• Plane — Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a like… …   The Collaborative International Dictionary of English

• Plane iron — Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a… …   The Collaborative International Dictionary of English

• Plane of polarization — Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a… …   The Collaborative International Dictionary of English

• Plane of projection — Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a… …   The Collaborative International Dictionary of English

• Plane of reflection — Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a… …   The Collaborative International Dictionary of English

• Plane of refraction — Plane Plane, n. [F. plane, L. plana. See {Plane}, v. & a.] 1. (Geom.) A surface, real or imaginary, in which, if any two points are taken, the straight line which joins them lies wholly in that surface; or a surface, any section of which by a… …   The Collaborative International Dictionary of English

• Infinity — In*fin i*ty, n.; pl. {Infinities}. [L. infinitas; pref. in not + finis boundary, limit, end: cf. F. infinit[ e]. See {Finite}.] [1913 Webster] 1. Unlimited extent of time, space, or quantity; eternity; boundlessness; immensity. Sir T. More. [1913 …   The Collaborative International Dictionary of English

• Infinity — In mathematics, infinity is often used in contexts where it is treated as if it were a number (i.e., it counts or measures things: an infinite number of terms ) but it is a different type of number from the real numbers. Infinity is related to… …   Wikipedia