One-sixtieth of a minute (6)

I believe the answer is:

second

(Other definitions for second that I've seen before include "Brief moment" , "Moment; musical interval" , "Time for a supporter" , "bit" , "Mo" .)

I've seen this clue in The Mirror.

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.