Knowledge about domain

Most generally, domain knowledge is the knowledge which is valid and directly used for a pre-selected domain of human endeavor or an autonomous computer activity.

Specialists and experts use and develop their own domain knowledge.

If the concept domain knowledge or domain expert is used we emphasize a specific domain which is an object of the discourse/interest/problem.

More particular, in software engineering, domain knowledge is knowledge about the environment in which the target system operates, for example, software agents. Domain knowledge is important, because it usually must be learned from software users in the domain ( as domain specialists/experts), rather than from software developers.

Communicating between end-users and software developers is often difficult. They must find a common language to communicate in. Developing enough shared vocabulary to communicate can often take a while.

Expert’s domain knowledge (frequently informal and ill structured) is transformed in computer programs and active data, for example in a set of rules in knowledge bases, by knowledge engineers.

For example:
Embedded controllers for automobile engines know how to control engines.
Medical software encodes knowledge and information about patients and medicine
Financial software encode formal rules related to purchasing, accounts, and inventory.