terminology question - "foreign function library"

[mirandacascade at yahoo.com]

I am prompted to make these inquiries after seeing the following link
to ctypes:

http://docs.python.org/lib/module-ctypes.html

in which ctypes is described as a foreign function library.

What is the definition of "foreign function library"?
Is the concept different from a "package"?
Is the concept different from a "module"?

Thank you.