Knight occupying space in which scutarius fought (5)
I believe the answer is:
arena
'knight occupying space in which scutarius fought' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'knight occupying space' is the wordplay.
'knight' becomes 'N' (chess abbreviation).
'occupying' indicates putting letters inside (inserted letters occupy or enter the word).
'space' becomes 'area' (I've seen this before).
'n' put into 'area' is 'ARENA'.
Can you help me to learn more?
(Other definitions for arena that I've seen before include "An era (anag.)" , "Place of combat" , "Amphitheatre's central space" , "O2, for example" , "Place of great activity" .)