See Also: Midfield Line or Center Line - Soccer(gambling)
Forward Line or Attacking Line - Ice Hockey(gambling)
His' line(medicine)
line-out(dictionary)
line-up(dictionary)
in-line(dictionary)
Hot line(health)
Above the Line(money)
S-BP line(medicine)
S-N line(medicine)

line (sh)




Basic element of Euclidean geometry.

Euclid defined a line as an interval between two points and claimed it could be extended indefinitely in either direction. Such an extension in both directions is now thought of as a line, while Euclid's original definition is considered a line segment. A ray is part of a line extending indefinitely from a point on the line in only one direction. In a coordinate system on a plane, a line can be represented by the linear equation ax + by + c = 0. This is often written in the slope-intercept form as y = mx + b, in which m is the slope and b is the value where the line crosses the y-axis. Because geometrical objects whose edges are line segments are completely understood, mathematicians frequently try to reduce more complex structures into simpler ones made up of connected line segments.