acclivity

noun

1. A slope or inclination of the earth, as the side of a hill, considered as ascending, in opposition to declivity, or descending; an upward slope; ascent.

   “how gaily vineyards and olives alternately chequer the acclivities”

   “she would walk […] as far as to the point where the acclivity from the valley began its first steep ascent to the outer world.”

   “Just below it leaned a tottering crag that would have toppled, starting an avalanche on an acclivity where no sliding mass could stop.”