A crannog is typically a partially or entirely artificial island, usually built in lakes and estuarine waters of Scotland, Wales, and Ireland.

What is the meaning of Crannog?

: an artificial fortified island constructed in a lake or marsh originally in prehistoric Ireland and Scotland.

What are crannogs used for?

Unlike the prehistoric pile dwellings around the Alps, which were built on the shores and not inundated until later, crannogs were built in the water, thus forming artificial islands. Crannogs were used as dwellings over five millennia, from the European Neolithic Period to as late as the 17th/early 18th century.