escarpment

n. slope, cliff

In geomorphology, an escarpment is a transition zone between different physiogeographic provinces that involves an elevation differential, often involving high cliffs. Most commonly, an escarpment, also called a scarp (from the Italian scarpa), is a transition from one series of sedimentary rocks to another series of a different age and composition. In such cases, the escarpment usually represents the line of erosional loss of the newer rock over the older (see also Cuesta).
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(n.)
A steep descent or declivity; steep face or edge of a ridge; ground about a fortified place, cut away nearly vertically to prevent hostile approach. See Scarp.
  

Noun
1. a long steep slope or cliff at the edge of a plateau or ridge; usually formed by erosion
(synonym) scarp
(hypernym) slope, incline, side
2. a steep artificial slope in front of a fortification
(synonym) escarp, scarp, protective embankment
(hypernym) fortification, munition