She's in the nest (3)
I believe the answer is:
hen
'she's' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'in the nest' is the wordplay.
'in' indicates a hidden word.
'HEN' can be found hidden inside 'the nest'.
Can you help me to learn more?
(Other definitions for hen that I've seen before include "Clucking female" , "Female bird" , "Laying bird" , "Coop resident" , "Domestic egg layer" .)