past participle of wear
"The old leather jacket was worn through at the elbows from years of hard work."
affected by wear; damaged by long use
"worn threads on the screw"
"a worn suit"
"the worn pockets on the jacket"
damaged and shabby as a result of much use
"The old leather jacket was worn thin at the elbows from years of hard work."
In plain English: Worn means something that has been used so much it looks old and damaged from being handled repeatedly.
"The old shoes were so worn that they had holes in the heels."
Usage: Use "worn" to describe items that are physically damaged or frayed from frequent handling, such as shoes with thin soles. This term specifically refers to the condition caused by usage rather than simply being old or unused.
The word worn is formed by analogy with other past participles, such as torn from tear and sworn from swear. It does not come from a different root but follows the same pattern used to create those related forms.