It's eaten as an aperitif (8)
I believe the answer is:
anisette
'an aperitif' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Maybe there's an association between them I don't understand?
'it's eaten' is the wordplay.
'it's eaten' can be anagrammed to 'ANISETTE'.
However, I am not sure how this is indicated.
'as' is the link.
Can you help me to learn more?
(Other definitions for anisette that I've seen before include "Liqueur with flavour of liquorice" , "Type of highly-flavoured liqueur" , "Liqueur; tetanise (anag.)" , "Aromatic cordial drink" , "Liquorice-flavoured liqueur" .)