A module is a software component or part of a program that contains one or more routines. One or more independently developed modules make up a program. An enterprise-level software application may contain several different modules, and each module serves unique and separate business operations.

Modules make a programmer's job easy by allowing the programmer to focus on only one area of the functionality of the software application. Modules are typically incorporated into the program (software) through interfaces.

Software applications include many different tasks and processes that cohesively serve all paradigms within a complete business solution. Early software versions were gradually built from an original and basic level, and development teams did not yet have the ability to use prewritten code.

The introduction of modularity allowed programmers to reuse prewritten code with new applications. Modules were created and bundled with compilers, in which each module performed a business or routine operation within the program.

For example, Systems, Applications and Products in Data Processing (SAP) - an enterprise resource planning (ERP) software - is comprised of several large modules (for example, finance, supply chain and payroll, etc.), which may be implemented with little or no customization. A classic example of a module-based application is Microsoft Word, which contains modules incorporated from Microsoft Paint that help users create drawings or figures.