Nothing really, although if you're being nit-picky, a string is rounded and a lace is flat. Most people use the two terms interchangeably.
a shoelace a shoelace a shoelace
The plural of shoelace my dear is shoelaces.
There are no perfect rhymes for the word shoestring.
The average shoelace weighs just about a gram or two, depending on the length of the shoelace.
the tip of the shoelace is an Aglet
the tips of the shoelace is called a aglet.
Shoelace, one word.
The end of a shoelace is called an aglet.
How many phonemes in the words locker and shoelace?
Where I live we usually say shoelace/s. Your shoelace is undone. Your shoelaces are undone.
ShoeString from the reawakening real name is Elijah
The metallic part of a shoelace is called an Aglet.