Brownfield
Formal
Brownfield (software development) describes the problem and the process of having to consider already existing systems when implementing new software systems.
Practical
The term brownfield was originally used in construction and development to reference land that at some point was occupied by a permanent structure. In a brownfield project the structure would need to be demolished or renovated. Today, the term brownfield project is used in many industries, including software development, to mean to start a project based on prior work or to rebuild (engineer) a product from an existing one.
