Slope of a beam is defines as
1
The deflection at any point on the axis of the beam is the distance between its position before and after loading
2
The slop of a beam at any point is the distance between its position before and after loading
3
The angle (radians) in which the tangent at the section makes with the original axis of the beam
4
The angle (radians) in which the tangent at the section makes with its position before and after loading