1. An independent piece of software which forms part of one or more larger programs. Different languages have different concepts of a module but there are several common ideas.

Modules are usually compiled seperately (in compiled languages) and provide an abstraction or information hiding mechanism so that a module's implementation can be changed without requiring any change to other modules. In this respect they are similar to objects in an object-oriented language, though a module may contain many procedures and/or functions which would correspond to many objects.

A module often has its own name space for identifiers so the same identifier may be used to mean different things in different modules.

2. An independent assembly of electronic components with some distinct function, e.g. a RAM module consisting of several RAM chips mounted on a small circuit board.