A prison bordering on a quantity of land (7)
I believe the answer is:
acreage
'land' is the definition.
(I've seen this in another clue)
'a prison bordering on' is the wordplay.
'prison' becomes 'cage' (cage is a kind of prison).
'bordering' means one lot of letters goes inside another.
'on' becomes 're' ('on' can be mean 'with reference to').
'cage' enclosing 're' is 'creage'.
'a'+'creage'='ACREAGE'
'a quantity of' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for acreage that I've seen before include "Measure used by farmer" , "Extent of (measured) land" , "expanse" , "plot" , "Farm" .)