
1) European archaeology
Found on
https://www.crosswordclues.com/clue/souterrain

Souterrain (from French `sous terrain`, meaning `under ground`) is a name given by archaeologists to a type of underground structure associated mainly with the Atlantic Iron Age. These structures appear to have been brought northwards from Gaul during the late Iron Age. Regional names include earth houses, fogous and Pictish houses. The term s...
Found on
http://en.wikipedia.org/wiki/Souterrain

underground chamber; earth-house
Found on
http://phrontistery.info/s.html

• (n.) A grotto or cavern under ground.
Found on
http://thinkexist.com/dictionary/meaning/souterrain/

In archaeology, a small underground chamber, often lined and roofed with boulders or stone slabs. Dating from prehistoric to historic times, they are found along the northern boundaries of the Old...
Found on
http://www.encyclo.co.uk/local/20688

An underground, or partially buried, curved like a banana chamber mostly made of stone. These are of unknown function, ; suggestions have been made that include ritual, (as some contain prehistoric and Roman carved stones), refuges from danger and as granaries. They are commonly found in Scotland - though a possible example was found at Milfieldhil...
Found on
http://www.encyclo.co.uk/local/20766

stone lined underground passage, usually leading to a chamber.
Found on
http://www.encyclo.co.uk/local/20935
Sou'ter·rain noun [ French See
Subterranean .] A grotto or cavern under ground. [ Obsolete]
Arbuthnot. Found on
http://www.encyclo.co.uk/webster/S/150
No exact match found.