Prison accommodating large family (4)
I believe the answer is:
clan
'family' is the definition.
(thesaurus)
'prison accommodating large' is the wordplay.
'prison' becomes 'can' (the can is American slang for prison).
'accommodating' means one lot of letters goes inside another.
'large' becomes 'l'.
'can' placed around 'l' is 'CLAN'.
(Other definitions for clan that I've seen before include "Tribe or collection of families under a cheiftain" , "Tribal family" , "Tribal group with common ancestor" , "(Scottish) family group" , "Scottish tribe" .)