What is the meaning of Wrapper?

Something that is wrapped around something else as a cover or protection: a wrapping.

An outer garment; a loose robe or dressing gown.

One who, or that which, wraps.

A construct, such as a class or module, that serves to mediate access to another.

(derogatory) a startup that sells technology that it largely does not itself make

Source: wiktionary.org