A source file or collection of files designed to be imported into any program.
A source file or collection of files that is part of a larger framework that may or may not be optional but depends in a large part on other modules within the framework.
Forth's analog to functions.
A package that brings together several libraries and modules for a specific purpose and is designed to lay on top of a framework as an addition to it (i.e. extend it), as opposed to abstracting it.
Stack Effect or Stack Diagram
The list of arguments and return values of a word. Here's a brief explanation of conventions used: