One with thick skin runs in circle to corral horse (5)
I believe the answer is:
'one with thick skin' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'runs in circle to corral horse' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'circle' becomes 'O' (O is a circle).
'to' means one lot of letters go next to another (I've seen this in other clues).
'corral horse' becomes 'h' (I am not sure about this - if you are sure you should believe this answer much more).
'ino' after 'h' is 'hino'.
Can you help me to learn more?
(Other definitions for rhino that I've seen before include "In brief, a large horned African animal" , "Large animal with a horn on its snout, in short" , "Ready" , "Thick-skinned beast" , "Funds" .)