Barrel slats (6)
I believe the answer is:
staves
'barrel slats' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for staves that I've seen before include "Verses. stanzas" , "Lines in a musical score; parts of a barrel" , "Lines in a music score" , "Barrel pieces; verses" , "Curved strips of wood in barrel" .)