Crossword Genius

Dressing, run after and join the others (7)

Ross

I believe the answer is:

catchup

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

'dressing' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for catchup that I've seen is " Sauce!".)

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