Camp bed set above a lake (7)
I believe the answer is:
coterie
'camp' is the definition.
('coterie' can be a synonym of 'camp')
'bed set above a lake' is the wordplay.
'bed set above' becomes 'cot' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a lake' becomes 'erie' (Lake Erie is one of the Canadian/US 'Great Lakes').
'cot'+'erie'='COTERIE'
Can you help me to learn more?
(Other definitions for coterie that I've seen before include "Small exclusive circle with a common purpose" , "Group of acquaintances" , "Exclusive group with shared interests" , "Group, band" , "Set" .)