Martini garnishes (6)
I believe the answer is:
olives
'martini garnishes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for olives that I've seen before include "Small green stone fruits, nice in cocktails" , "Small green Mediterranean tree fruits" , "Fruits from the tree of peace" , "The fruits are important source of oil" , "Yellowish green fruits" .)