"Programming domain" in computer science and computer programming is a general term that refers to the field or problem that a program, programming language or language syntax is designed to operate within or solve. The term most often is used when referencing domain-specific programming languages, which are programming languages that are designed to specifically address the needs of a single field or problem. There is no real formal specification for what is or is not a programming domain, although there are some commonly used broad categories, such as business, Internet and networking, and some more specific domains, such as optical recognition or messaging. The term is fairly abstract, so it most often is applied during academic research or during the design stage of software development.
One purpose for defining a programming domain can be to help model a domain-specific programming language. This means that, if a programming domain is defined as Internet email, then the programming language will be designed during the initial design stage specifically to address issues related only to Internet email, usually at a very high level for the end programmer. In this example, a domain-specific programming language for the Internet email programming domain could include commands such as "send_to_address" or "check_valid_address" that are used to address specific network issues associated with Internet email but have no broader, more general purpose beyond that.
In a wider sense, a programming domain also can be an important concept when using domain-driven design. This type of software design pattern gears the programming language and the entire application infrastructure and control logic around the domain. By connecting the programming domain to different levels and stages of development, the context of certain application parts emerges and, in very complex programs, can make it easier for programmers and engineers to solve problems and visualize the inner functioning of the program.
A complication that can be encountered in the wider software development industry is that, while many development teams might be using a programming domain and domain-related models, there is no standardization about what a domain actually entails, how it is named or how it should be visualized. What one company might call a business domain might be called an enterprise domain by another company. When applications, patterns and frameworks are developed for a specific domain by one company, they can be published, advertised or sold as development tools or solutions for another company that might be working within the same domain. Without a standard for domain naming, existing domain-based solutions could go completely unnoticed.