Pit dog rarely outside (8)
I believe the answer is:
colliery
'pit' is the definition.
('colliery' can be a synonym of 'pit')
'dog rarely outside' is the wordplay.
'dog' becomes 'collie' (collie is a kind of dog**).
'outside' suggests removing the centre.
'rarely' with its middle taken out is 'ry'.
'collie'+'ry'='COLLIERY'
(Other definitions for colliery that I've seen before include "Coal-mining establishment" , "Coal mine" , "Where a coalminer goes to work" , "Mining complex" , "Grimethorpe?" .)