One might attach to a toddler's backpack (5)

I believe the answer is:

leash

(Other definitions for leash that I've seen before include "Rope or chain restraint" , "Strip for leading, a dog say" , "A dog walker may use it" , "Animal restraint" , "Line for controlling a dog" .)

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.