Cat straddling small horse — Shetland, perhaps (7)
I believe the answer is:
toponym
'shetland perhaps' is the definition.
I can't tell whether this defines the answer.
'cat straddling small horse' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'straddling' is an insertion indicator (straddle can mean to lie on both sides of).
'small horse' becomes 'pony' (I've seen this before).
'tom' placed around 'pony' is 'TOPONYM'.
Can you help me to learn more?
(Other definitions for toponym that I've seen before include "Derby, for example" , "Geographical word for a place name" , "Shetland for instance" , "Sevenoaks, say" , "Word derived from place name" .)