Nanny trains where plants are reared (7)
I believe the answer is:
nursery
'where plants are reared' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'nanny trains' is the wordplay.
'nanny' becomes 'nurse' (synonyms).
'trains' becomes 'ry' (abbreviation for railway).
'nurse'+'ry'='NURSERY'
Can you help me to learn more?
(Other definitions for nursery that I've seen before include "sort of rhyme" , "Where you could see young" , "facility for development" , "Creche" , "Where trees are tended" .)