Flaxseed (7)
I believe the answer is:
linseed
'flaxseed' is the definition.
(I know that flaxseed can be written as linseed)
This is the entire clue.
(Other definitions for linseed that I've seen before include "Oil produced from flax" , "Enisled (anag.)" , "Flax plant product providing oil" , "Flax product, a source of oil" , "Source of plant oil" .)