One of three getting name checked in Great Hosannah (9)
I believe the answer is:
musketeer
'one of three getting name' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see a link between them that I don't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for musketeer that I've seen before include "Old soldier with shoulder gun with a long barrel" , "One of Dumas' trio with guns" , "Athos, Porthos or Aramis, say" , "Armed soldier (hist.)" , "Athos perhaps" .)