Slope

Slope - In mathematics, the slope of a straight line (within a Cartesian coordinate system) is a measure for the "steepness" of said line. With an understanding of algebra and geometry, one can calculate the slope of a straight line; with calculus, one can calculate the slope of the tangent to a curve at a point.

http://www.wtamu.edu/academic/anns/mps/math/mathlab/int_algebra/int_alg_tut15_slope.htm