Row, some quarrel in essence (4)
I believe the answer is:
line
'row' is the definition.
(as in a row of things)
'some quarrel in essence' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'LINE' can be found hidden inside 'quarrel in essence'.
(Other definitions for line that I've seen before include "Dress" , "Policy - file" , "Some poetic feet; boundary, when drawn" , "dash one end to the other" , "Long narrow mark" .)