Carthorse transported many musicians (9)
I believe the answer is:
orchestra
'many musicians' is the definition.
'orchestra' can be an answer for 'musicians' (I've seen this before). I am not sure about the 'many' bit.
'carthorse transported' is the wordplay.
'transported' indicates an anagram.
'carthorse' anagrammed gives 'ORCHESTRA'.
Can you help me to learn more?
(Other definitions for orchestra that I've seen before include "Other cars (anag.)" , "many players" , "An assembly of musicians with various instruments" , "Gamelan, for instance" , "Musicians, maybe in theatre" .)