Roman seahorse? (4)
I believe the answer is:
mare
'roman seahorse?' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
This is the entire clue.
Can you help me to learn more?
(Other definitions for mare that I've seen before include "Adult female horse" , "Ream (anag)" , "Horse; lunar sea" , "Female equine animal" , "Adult female zebra" .)