Narrow strip of wood (4)
I believe the answer is:
lath
'narrow strip of wood' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lath that I've seen before include "Strip of wood used with plaster" , "Narrow thin strip of wood" , "Wood underlying plaster" , "Thin wood strip supporting plaster" , "Halt bearing strip of wood" .)