Mediterranean tree (5)
I believe the answer is:
olive
'mediterranean tree' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for olive that I've seen before include "Yellowy-green colour and fruit" , "Evergreen Mediterranean tree" , "Girl's name - colour" , "Greyish-green; fruit" , "It's branch is a symbol of peace" .)