Crossword Genius

Here, time's up! (5,5)

Ross

I believe the answer is:

clock tower

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

'here' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'time's up' is the wordplay.
I cannot really understand how this works, but
'time' could be 'clock' (synonyms) and 'clock' is found in the answer.
The remaining letters 'tower' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for clock tower that I've seen before include "one looked up to for a time?" , "will it hold up the enemy's progress?" , "Big Ben, for example" .)

I've seen this clue in The Guardian.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.