A spare one might be kept in the boot (4)

I believe the answer is:

tyre

(Other definitions for tyre that I've seen before include "Wheel's rubber tube" , "Rubber part of wheel" , "Biblical town" , "Pneumatic wheel cover" , "Rubber wheel; port" .)

I've seen this clue in The New York Times.

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.