Crossword Genius

Most important character on all sides today (7)

Ross

I believe the answer is:

leading

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

This clue might be a double definition.

'most important' is the first definition.
(I've seen this before)

'character on all sides today' is the second definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

Can you help me to learn more?

(Other definitions for leading that I've seen before include "In first place; space between lines of print" , "Main" , "Female top of the bill" , "in van" , "Aligned in front" .)

I've seen this clue in the Irish Times.
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