nether region

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• noun often pluralized Hell; a realm beneath the surface of the earth conceived as the abode of the souls of the dead and, sometimes, as the abode of demons or evil spirits.
• noun often pluralized, by extension A place which is subterranean or enclosed beneath a surface, especially one which is dark, dank, or otherwise inhospitable.
• noun often pluralized, euphemistic The groin or buttocks.

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

• noun (Christianity) the abode of Satan and the forces of evil; where sinners suffer eternal punishment