lake dwelling

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A dwelling, especially a prehistoric dwelling, built on piles in a shallow lake.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a prehistoric structure, built over shallow waters, such as a lake or marsh, supported on piles or artificial mounds of earth or wood

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun dwelling built on piles in or near a lake; specifically in prehistoric villages