Combined places to study old, unknown card game (8)
I believe the answer is:
oxbridge
'combined places to study' is the definition.
I can't tell whether this definition defines the answer.
'old unknown card game' is the wordplay.
'old' becomes 'o' (abbreviation).
'unknown' becomes 'x' (algebra).
'card game' becomes 'bridge' (bridge is a kind of card game).
'o'+'x'+'bridge'='OXBRIDGE'
Can you help me to learn more?
(Other definitions for oxbridge that I've seen before include "Related to Britain's two oldest universities" , "Elite academia" , "Oxford and Cambridge Universities" , "Elite institutions shortly" , "linking two top-quality bodies" .)