Sequence that tennis player may break (6)

I believe the answer is:

string

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

'sequence' is the definition.
(I know that string is a type of sequence)

I don't understand how the remainder of the clue works.

(Other definitions for string that I've seen before include "A lightweight cord" , "Procession" , "yarn" , "one of four on violin" , "tier" .)

I've seen this clue in The Independent.

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.