Chardonnay, for one (5)
I believe the answer is:
grape
'chardonnay for one' is the definition.
(I know that Chardonnay is a type of Vitis vinifera)
This is the entire clue.
(Other definitions for grape that I've seen before include "Green/black fruit" , "Vine fruit" , "It grows on the vine" , "Vineyard fruit" , "Small fruit; type of shot" .)