It provides accommodation in the detention centre (3)
I believe the answer is:
inn
'it provides accommodation' is the definition.
The definition suggests a singular noun which matches the answer.
'in the detention centre' is the wordplay.
'centre' says to take the centre.
The middle letter of 'detention' is 'n'.
'in'+'n'='INN'
Can you help me to learn more?
(Other definitions for inn that I've seen before include "One of Lincoln's" , "bar" , "pubs?" , "eg the Tabard" , "Jamaica, for one" .)