Candle holder has a trick in each odd socket (6)
I believe the answer is:
sconce
'candle holder' is the definition.
(sconce is a kind of candle holder)
'a trick in each odd socket' is the wordplay.
I cannot really understand how this works, but
'trick' could be 'con' (a con is a fraud or trick) and 'con' is found in the answer.
This explanation may well be incorrect...
'has' is the link.
Can you help me to learn more?
(Other definitions for sconce that I've seen before include "Ornamental candle holder" , "Wall bracket, for candles say" , "wit at one time" , "Wall bracket for a candle" , "Ornamental wall-bracket as for candle or light" .)