Stays as Cornish capital takes the place of another county's capital (6)

I believe the answer is:

corset

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

'stays' is the definition.
(stays can refer to a corset)

I can't explain the remainder of the clue.

(Other definitions for corset that I've seen before include "A lady's old foundation garment" , "Female undergarment" , "Sector (anag)" , "Item of underwear" , "Restraining undergarment" .)

I've seen this clue in the Sydney Morning Herald.

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.