Chicken with a portion of potatoes, tinned (5)
I believe the answer is:
capon
'chicken' is the definition.
(capon is a kind of chicken)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for capon that I've seen before include "for lunch, perhaps" , "Castrated fowl, for eating" , "Male chicken for eating" , "one fattened specially" , "Castrated rooster fattened for eating" .)