Porridge and rice can make allowance for meals (13)
I believe the answer is:
incarceration
'porridge' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'rice can make allowance for meals' is the wordplay.
'make' indicates an anagram.
'allowance' becomes 'rat' (I've seen this in another clue).
'for meals' becomes 'ion' (I can't justify this - if you can you should give a lot more credence to this answer).
'rice'+'can'='ricecan'
'ricecan' anagrammed gives 'incarce'.
'incarce'+'rat'+'ion'='INCARCERATION'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for incarceration that I've seen before include "Judicial confinement" , "Jail" , "Imprisonment" , "Captivity" .)