Tank from Germany is housed in Swiss physics lab (7)
I believe the answer is:
cistern
'tank' is the definition.
(I know that cistern is a type of tank)
'germany is housed in swiss physics lab' is the wordplay.
I cannot really see how this works, but
'is' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'from' acts as a link.
Can you help me to learn more?
(Other definitions for cistern that I've seen before include "WC water tank" , "Tank, reservoir" , "Water storage tank" , "Water container" , "Vat" .)