Lunch for a pet at home (6)
I believe the answer is:
tiffin
'lunch' is the definition.
('tiffin' can be a synonym of 'lunch')
'a pet at home' is the wordplay.
'a pet' becomes 'tiff' (I've seen this before).
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'tiff'+'in'='TIFFIN'
'for' is the link.
(Other definitions for tiffin that I've seen before include "Light (Indian) meal" , "Midday meal for members of the British Raj in India" , "(Anglo Indian) lunch" , "Lunch (British Raj)" , "Indian midday meal" .)