In geometry, a straight line, usually abbreviated line, is an infinitely long object with no width, depth, or curvature, an idealization of such physical...

In geometry, a line segment is a part of a straight line that is bounded by two distinct endpoints (its extreme points), and contains every point on the...

Until the 19th century, geometry was almost exclusively devoted to Euclidean geometry, which includes the notions of point, line, plane, distance, angle...

postulate of Euclidean geometry is replaced with: For any given line R and point P not on R, in the plane containing both line R and point P there are...

In geometry, central lines are certain special straight lines that lie in the plane of a triangle. The special property that distinguishes a straight line...

Euclidean geometry is a mathematical system attributed to ancient Greek mathematician Euclid, which he described in his textbook on geometry, Elements...

non-Euclidean geometry consists of two geometries based on axioms closely related to those that specify Euclidean geometry. As Euclidean geometry lies at the...

affine geometries and Euclidean geometry is a special instance of this type of geometry. In some other geometries, such as hyperbolic geometry, lines...

elliptic geometry. In elliptic geometry, two lines perpendicular to a given line must intersect. In fact, all perpendiculars to a given line intersect...

Look up Line, line, or líne in Wiktionary, the free dictionary. Line most often refers to: Line (geometry), object that has zero thickness and curvature...