What is pothouse?

Some articles on pothouse:

Wednesbury Oak Loop - Route
... Pothouse Bridge carries Salop Road over the canal, and then another basin served the Regent Iron Works ... Deepfields Junction) SO938950 BCN Main Line Pothouse Bridge Junction 52°33′31″N 2°03′58″W / 52.5585°N 2.0662°W / 52.5585 -2.0662 (Pothouse Bridge Junction) SO955956 ...