Blade used by a cutter perhaps (3)
I believe the answer is:
oar
'blade' is the definition.
(blade is the word for oar in competitive rowing)
'a cutter perhaps' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
The remaining letters 'or' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'used by' is the link.
Can you help me to learn more?
(Other definitions for oar that I've seen before include "Rowing boat operator" , "Rower's flat blade" , "spoon?" , "One of an eight" , "Pole for rowing" .)