Is there an expression for an abrupt change in height? I’m looking for a word for the edge of the change, like in the German word Geländekante.
A cliff or precipice is at the boundary to an abrupt change in altitude.
a steep rock face, especially at the edge of the sea.
synonyms: precipice, rock face, crag, bluff, ridge, escarpment, scar,
I don't speak German, but looking at this page it seems to me Geländekante can apply to any abrupt change in "level".
Those examples range from "height discontinuities" of hundreds/thousands of feet (cliffs, Ayers Rock) to mere inches (kerb between road and pavement, small mismatch in a loading bay area). So I think the short answer is there is no equivalent "generic" word or common expression for this in English.
1: At the "geological" level there are lots of terms (cliff, escarpment, bluff, etc.), with the same or overlapping meanings.
2: Somewhere in the middle - usually from the "above" perspective, with emphasis on the danger of falling over the edge - are terms like precipice, drop.
3: At smaller scales (the most likely context where you'd need a more general-purpose term) the best bet is probably step (Mind the step = Don't trip over the upcoming small change in level).
There are dozens of words for these things that vary in aspect, specificity, origin, and region. Sometimes they emphasize the vertical aspect; other times the line at the top or bottom. Some are for collections of these things; others for singular instances.
- combs ridge
- castle rock
Some of these terms are common and general; others rare and specific. There are many more. Some are found in every dictionary; others only in specialty lexicons devoted to geography. One of the latter can be found at the web site Home Ground: Language for an American Landscape.
Scarp, or escarpment. Wikipedia:
- Cliff, a significant vertical, or near vertical, rock exposure
- Escarpment, a steep slope or long rock that occurs from erosion or faulting and separates two relatively level areas of differing elevations