Mount mean equine in North America (9)
I believe the answer is:
parnassus
'mount' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see a link between them that I can't see?
'mean equine in north america' is the wordplay.
'mean' becomes 'par' (average score on a golf course).
'equine' becomes 'ass' (ass is a kind of equine).
'in' means one lot of letters goes inside another.
'north' becomes 'N' (abbreviation).
'america' becomes 'US' (United States).
'n'+'us'='nus'
'ass' inserted within 'nus' is 'nassus'.
'par'+'nassus'='PARNASSUS'
Can you help me to learn more?
(Other definitions for parnassus that I've seen before include "Greek mountain sacred to Apollo" , "Mythological home of the Muses" , "Mount sacred to the Muses" , "Mountain sacred to Apollo and the Muses" , "Mountain where Delphi is located" .)