all hospitals as its domain. In a computer programming design, one defines a domain by delineating a set of common requirements, terminology, and functionality for any software program constructed to solve a problem in the area of computer programming, known as domain engineering. The word "domain" is also taken as a synonym of application domain.

Domain in the realm of software engineering commonly refers to the subject area on which the application is intended to apply. In other words, during application development, the domain is the "sphere of knowledge and activity around which the application logic revolves." --Andrew Powell-Morse