Cone source (3)
I believe the answer is:
fir
'cone source' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for fir that I've seen before include "Coniferous tree" , "Evergreen tree for Irish men?" , "Pine tree for Gaelic men?" , "Scots pine" , "Tree for Irishmen" .)