scarp
Concise Oxford English Dictionary © 2008 Oxford University Press:
scarp/skɑːp/
▶noun a very steep bank or slope; an escarpment.
■ the inner wall of a ditch in a fortification.
▶verb cut or erode so as to form a scarp.– origin C16 (with ref. to fortification): from Ital. scarpa.
'scarp' also found in these Oxford entries:

