Slope of a line is the ratio of the amount y increases to the amount x increases.OR in other words, Slope of surface or line inclined from horizontal or vertical line, slant up or down.
I think it is increase of height on a path where downwards force act with more strength and decreases acceleration
may be its denote as acceleration

In mathematics, the slope or gradient of a line is a number that describes both the direction and the steepness of the line.[1] Slope is often denoted by the letter m; there is no clear answer to the question why the letter m is used for slope, but it might be from the “m for multiple” in the equation of a straight line “y = mx + b” or “y = mx + c”.[2]

The slope of a line is a number that describes both the direction and the steepness of the line.

Slope is the inclination b/w a line and to the angle with the positive direction of the axes. Slope =m=tan theta.
Slope simply means inclination of a line with positive x axis. Slope = tan theta, where theta is the angle made with x axis and y2-y1/x2-x1Slope of x axis = tan 0= 0Slope of y axis = tan 90= not defined.
Slope(M) = ∆Y/∆X=y2-y1/x2-x1=tanøSlope is the angle of a line with x axis….a line parallel to x axis will have a slope of 1.
M =tan o_
It is line which create an angel on positive x axis