"The Thesaurus is a controlled vocabulary developed by the United Nations Educational, Scientific and Cultural Organisation (UNESCO) which includes subject terms for the following areas of knowledge: education, science, culture, social and human sciences, information and communication, and politics, law and economics. It also includes the names of countries and groupings of countries: political, economic, geographic, ethnic and religious, and linguistic groupings. The UNESCO Thesaurus allows subject terms to be expressed consistently, with increasing specificity, and in relation to other subjects. It can be used to facilitate subject indexing in libraries, archives and similar institutions."