(definition) by RubenAzarja (print)
Terp (?), n.
Frisian (and Dutch) word for a historical refuge hill in a frequently flooded area. Best single word description in English would be mound or knoll. Also: village (old Frisian) or burial mound.
A terp can be as high as 15 m. Van Dale
Many cities in Friesland have been built on a terp. In Groningen, this refuge hill is called wierde.