The most common and most likely answer to this crossword clue is the 4 letter word NORM
I've seen this crossword clue in The Guardian
N
O
R
M
More clues leading to the result NORM
- Choice of adjacent letters seen as benchmark
- Standard choice of letters
- The average Pole or Frenchman?
- Invaders with no answer – you might expect that
- Male model?
- Standard number assigned to soldiers
- Lady’s incomplete pattern
- Mean fellow?
- Over my dead body, jolly pattern
- Standard choice of letters from middle of the alphabet
Buddy explains!

The straight part
We know that "The average" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the average = norm.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NORM mean?
NORM noun- That which is normal or typical.
- A rule that is enforced by members of a community.
- A sentence with non-descriptive meaning, such as a command, permission or prohibition.
- A function, generally denoted v\mapsto\left
- v\right
- or v\mapsto\left\
- v\right\
- , that maps vectors to non-negative scalars and has the following properties:
- A high level of performance in a chess tournament, several of which are required for a player to receive a title.
- To endow (a vector space, etc) with a norm.