Source : Webster's Revised Unabridged Dictionary (1913)

Slope \Slope\, n. [Formed (like abode fr. abide) from OE.
   slipen. See {Slip}, v. i.]
   1. An oblique direction; a line or direction including from a
      horizontal line or direction; also, sometimes, an
      inclination, as of one line or surface to another.

   2. Any ground whose surface forms an angle with the plane of
      the horizon.

            buildings the summit and slope of a hill.
                                                  --Macaulay.

            Under the slopes of Pisgah.           --Deut. iv.
                                                  49. (Rev.
                                                  Ver.).

   Note: A slope, considered as descending, is a declivity;
         considered as ascending, an acclivity.

   {Slope of a plane} (Geom.), the direction of the plane; as,
      parallel planes have the same slope.