One end of a battery (5)
I believe the answer is:
anode
'one end of a battery' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for anode that I've seen before include "Eg, battery terminal" , "that comes out of a cell?" , "Negative terminal of a battery" , "Electrical terminal" , "A cell terminal" .)