Species of onion (7)
I believe the answer is:
shallot
'species of onion' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for shallot that I've seen before include "One may get into a stew" , "Type of 12" , "Small onion" , "salad vegetable" , "Small onion-like bulb used for seasoning" .)