Wrapper

In computer science, a wrapper is a piece of code which is combined with another piece of code to determine how that code is executed.

The wrapper acts as an interface between its caller and the wrapped code. This may be done for compatibility, e.g. if the wrapped code is in a different programming language or uses different calling conventions, for security, e.g. to prevent the calling program from executing certain functions, to provide a level of emulation, e.g. a DirectX API which uses OpenGL to render its graphics.

The implication is that the wrapped code can only be accessed via the wrapper.