" ACCLIVITY  (ACCLI'VITY)   n.s.[from acclivus, Lat.] The steepness or slope of a line inclining to the horizon, reckoned upwards; as, the ascent of an hill is the acclivity, the descent is the declivity.Quincy. "

― Samuel Johnson , A Dictionary of the English Language (Complete and Unabridged in Two Volumes), Volume One