wrapper

the covering (usually paper or cellophane) in which something is wrapped

a loose dressing gown for women

cloak that is folded or wrapped around a person

a detachable cover or paper surrounding a book or magazine

A wrapper is a protective cover or outer layer used for a book or other publication. It can refer to the dust jacket of a book, which provides protection and often features artwork or promotional information, or to a simpler cover used to encase the book during shipping or handling. The wrapper helps safeguard the book from damage and can also add a decorative or informative element.