ole The term domain expert is frequently used in expert systems software development, and there the term always refers to the domain other than the software domain. a domain expert is a person with special knowledge or skills in a particular area of endeavor. (an accountant is an expert in the domain of accountancy, for example.Role • The term domain expert is frequently used in expert systems software development, and there the term always refers to the domain other than the software domain. A domain expert is a person with special knowledge or skills in a particular area of endeavor. (An accountant is an expert in the domain of accountancy, for example.)