Male astride little horse in New Forest for instance (7)

I believe the answer is:
toponym
'new forest for instance' is the definition.
I can't judge whether this definition defines the answer.
'male astride little horse' is the wordplay.
'male' becomes 'tom' (tom can mean a male cat).
'astride' means one lot of letters goes inside another.
'little horse' becomes 'pony' (a pony is a little horse).
'tom' going around 'pony' is 'TOPONYM'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for toponym that I've seen before include "Geographical word for a place name" , "Word derived from place name" , "Sevenoaks, say" , "Shetland for instance" , "Derby, for example" .)
