Fit in compartment (7)
I believe the answer is:
install
'fit' is the definition.
(thesaurus)
'in compartment' is the wordplay.
'compartment' becomes 'stall' (I have seen 'Stable compartment ' mean 'stall' so perhaps 'compartment' could also mean 'stall').
'in'+'stall'='INSTALL'
(Other definitions for install that I've seen before include "Lodge" , "place in office" , "Station" , "Set up, ready for use" , "Settle" .)