Measure the piece of wood (3)
I believe the answer is:
rod
This clue might be a double definition.
'measure' is the first definition.
(rod is a kind of measure)
'piece of wood' is the second definition.
'rod' can be an answer for 'piece' (both are slang terms for a gun). I am unsure of the 'of wood' bit.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for rod that I've seen before include "Instrument of punishment" , "The fly fisherman's stick" , "Little boy" , "Wand - fishing stick" , "Staff" .)