At the heart of some recent rallies (7)

I believe the answer is:

central

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

'at' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.

'heart of some recent rallies' is the wordplay.
'heart of' indicates a hidden word.
'CENTRAL' is hidden within 'some recent rallies'.

'the' is the link.

Can you help me to learn more?

(Other definitions for central that I've seen before include "Focal" , "Extremely important" , "Every answer here has one such letter" , "Most important, principal" , "Near the middle" .)

I've seen this clue in the Evening Standard.

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.