A shoestring is a long, thin piece of material that you use to tie your shoes.
Shoestrings are usually practical and everyday things.
Examples:
I need to tie my shoes with a shoestring.
The shoestring is too short to tie my shoes.
She bought new shoes with red shoestrings.
I found a shoestring on the ground and used it to tie my shoes.
He tied his shoes with a very long shoestring.
I can't find my shoestring, so I can't tie my shoes!