Part of a strict routine diet (5)
I believe the answer is:
trout
'part of a strict routine diet' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'of a strict routine diet' is the wordplay.
'of' indicates a hidden word.
'TROUT' is hidden in the letters of 'strict routine diet'.
Can you help me to learn more?
(Other definitions for trout that I've seen before include "Fish (associated with Schubert?)" , "Tasty fish, perhaps of rainbow kind" , "Rainbow, for example" , "one often tickled?" , "Unattractive old woman" .)