Barrel slat (5)
I believe the answer is:
stave
'barrel slat' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stave that I've seen before include "Set of lines on which musical notes are written" , "Strip of wood" , "System of five horizontal lines in written music" , "Wooden piece of barrel" , "Part of a wooden barrel" .)