The Collaborative International Dictionary
Plane \Plane\, a. [L. planus: cf. F. plan. See Plan, a.] Without elevations or depressions; even; level; flat; lying in, or constituting, a plane; as, a plane surface.
Note: In science, this word (instead of plain) is almost exclusively used to designate a flat or level surface.
Plane angle, the angle included between two straight lines in a plane.
Plane chart, Plane curve. See under Chart and Curve.
Plane figure, a figure all points of which lie in the same plane. If bounded by straight lines it is a rectilinear plane figure, if by curved lines it is a curvilinear plane figure.
Plane geometry, that part of geometry which treats of the relations and properties of plane figures.
Plane problem, a problem which can be solved geometrically by the aid of the right line and circle only.
Plane sailing (Naut.), the method of computing a ship's place and course on the supposition that the earth's surface is a plane.
Plane scale (Naut.), a scale for the use of navigators, on which are graduated chords, sines, tangents, secants, rhumbs, geographical miles, etc.
Plane surveying, surveying in which the curvature of the earth is disregarded; ordinary field and topographical surveying of tracts of moderate extent.
Plane table, an instrument used for plotting the lines of a survey on paper in the field.
Plane trigonometry, the branch of trigonometry in which its principles are applied to plane triangles.
WordNet
n. the geometry of 2-dimensional figures
Wikipedia
In mathematics, plane geometry may refer to the geometry of a two-dimensional geometric object called a plane.
Most times it refers to Euclidean plane geometry, the geometry of plane figures,
More specifically it can refer to:
- Euclidean plane geometry:
- Cartesian geometry, the study of geometry using a coordinate system
- Two-dimensional space
- synthetic geometry, the study of geometry using a logical deduction and compass and straightedge constructions
- geometry of a projective plane,
- often the real projective plane,
- but possibly the complex projective plane or projective plane defined over some other field,
- either infinite or finite, such as the Fano plane, or others;
- geometry of an affine plane,
- geometry of a non-Euclidean plane,
- either the hyperbolic plane,
- or the elliptic plane,
- or the geometry of the related two-dimensional spherical geometry.
Usage examples of "plane geometry".
If we imagine constructions to be made with rigid rods in the surface (similar to that above with the marble slab), we should find that different laws hold for these from those resulting on the basis of Euclidean plane geometry.
A phonograph record is, actually, a long, helical spiral, and can be represented entirely in a plane geometry sort of way: in space, although I suppose you can talk about the stylus accumulating the music as it goes along.
In fact, the class looked like any group of American teenagers trying to stay awake during last-period plane geometry, slumped down in their seats and glancing at their watches.