Those often caged in prison house (8)
I believe the answer is:
canaries
'those often caged' is the definition.
I can't judge whether this defines the answer.
'prison house' is the wordplay.
'prison' becomes 'can' (the can is American slang for prison).
'house' becomes 'aries' (Aries is an example).
'can'+'aries'='CANARIES'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for canaries that I've seen before include "holiday resort" , "Islands and yellowish birds" , "Mediterranean islands and yellow birds" , "Yellow songbirds or Spanish islands off Africa" , "The birds can arise" .)