Key to hanging plant fibre for weaving (4)
I believe the answer is:
flax
'weaving' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'key to hanging plant fibre' is the wordplay.
'key' becomes 'f' (musical key).
'to hanging plant fibre' becomes 'lax' (I can't explain this - if you can you should give a lot more credence to this answer).
'f'+'lax'='FLAX'
'for' is the link.
Can you help me to learn more?
(Other definitions for flax that I've seen before include "Plant cropped for linen" , "Fibre woven to make linen" , "Blue flowering plant cultivated for its seeds and fibre" , "Linen fibres" , "Plant from which linen is made" .)