The usual, of course (3)
I believe the answer is:
par
This clue might be a double definition.
'the usual' is the first definition.
'course' is the second definition.
I know that 'course' relates to this answer. I also know that both the answer and definition are singular nouns
'of' acts as a link.
Can you help me to learn more?
(Other definitions for par that I've seen before include "Usual score at golf" , "Norm" , "Accepted standard" , "Accepted level" , "Face value; equal standing" .)