souterrain
/ˈsuːtəreɪn
/noun chiefly Archaeology
An underground chamber or passage.Irish houses, moreover, were now often built in close association with souterrains, stone-lined, underground passages, sometimes as much as 100 metres in length....
- The situation in south-west England is broadly comparable to southern Scotland, with rounds (small enclosed homesteads), courtyard houses, and souterrains present, though only one villa has been recognized west of Exeter.
- A massive prehistoric underground bunker - or souterrain - has been excavated near Dundee.
Origin
Mid 18th century: from French, from sous 'under' + terre 'earth'.