Crossword Genius

On the list as a small boy (3)

Ross

I believe the answer is:

reg

I'm a little stuck... Click here to teach me more about this clue!

'boy' is the definition.

'on the list as a small' is the wordplay.
I cannot quite see how this works, but
'on' could be 're' (regarding) and 're' is present in the answer.
A single letter 'g' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app