pediment

Concise Oxford English Dictionary © 2008 Oxford University Press:
pediment/ˈpedɪmənt/

▶noun

• 1 Architecture the triangular upper part of the front of a classical building, typically surmounting a portico.

• 2 Geology a broad expanse of rock debris extending outwards from the foot of a slope.

– derivatives
pedimental adjective,
pedimented adjective.

– origin C16 (as periment): perh. an alt. of pyramid.