Wikipedia
Steilhang
A Steilhang (pl: Steilhänge) is a geoscientific term for a steep mountainside or hillside (or a part thereof), the average slope of which is greater than 1:2 or 30°. Leser defines a steilhang as a mountainside with an incline of between 16° and 60°, slopes of between 30° and 60° being described as "very steep" (übersteil) and anything over 60° being a rock face (Wand).
The term is German for "steep slope/mountainside/hillside", "escarpment" or "steep face". The word Hang in this compound may be similar in origin to the English word "hangar" used to mean woods on steep hillsides e.g. for the East Hampshire Hangers.