UCAS uncovered shortage, less university space available (8)

I believe the answer is:
capacity
'space available' is the definition.
I can't judge whether this definition defines the answer.
'ucas uncovered shortage less university' is the wordplay.
'uncovered' indicates the central letters.
'shortage less' becomes 'pa' (I can't explain this - if you can you should believe this answer much more).
'university' becomes 'city university' (city university is a kind of university).
The middle of 'ucas' is 'ca'.
'ca'+'pa'+'city'='CAPACITY'
Can you help me to learn more?
(Other definitions for capacity that I've seen before include "The amount that something can hold" , "how much can one take?" , "Potential - role" , "Space -- role" , "Maximum amount that can be contained" .)
