The term codebase, or code base, is used in software development to mean the whole collection of source code used to build a particular application or component.
The codebase for a project is typically stored in a source control repository. A source code repository is a place where large amounts of source code are kept, either publicly or privately. They are often used by multi-developer projects to handle various versions and developers submitting various patches of code in an organized fashion. Subversion and Mercurial are popular tools used to handle this workflow, and are common in open source projects.
