What is "fogou"

n. (context archaeology English) A Cornish souterrain, a underground, dry-stone-walled chamber open on two ends.

A fogou or fougou (pronounced "foo-goo") is an underground, dry-stone structure found on Iron Age or Romano-British defended settlement sites in Cornwall. Fogous have similarities with souterrains or earth-houses of northern Europe and particularly Scotland including the Orkney Islands. Fewer than 15 confirmed fogous have been found.