Tree with acorns (3)
I believe the answer is:
oak
'tree with acorns' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oak that I've seen before include "From little acorns does it grow" , "Building timber" , "Tree of the genus Quercus" , "Common deciduous tree" , "door at Oxford" .)