"The IEEE Thesaurus is a controlled vocabulary of over 9,000 descriptive engineering, technical, and scientific terms as well as IEEE-specific society terms. The thesaurus represents terminology and vocabulary usage drawn from IEEE transactions and journal articles, conference papers, and standards. The vocabulary uses American-based spellings with cross references to British variant spellings. The scope and structure of the IEEE Thesaurus reflect the engineering and scientific disciplines that comprise the societies, councils, and communities of IEEE in addition to the technologies IEEE serves. The IEEE Thesaurus contains controlled vocabulary referred to as descriptors or preferred terms*. These descriptors are considered the preferred terms for index usage. Thesaurus construction is based on the ANSI/NISO Z39.19-2005 standard, Guidelines for the Construction, Format, and Management of Monolingual Controlled Vocabularies. Each descriptor included in the thesaurus represents a single concept or unit of thought. The scope of the descriptors is based on the material as presented in IEEE periodical articles, conference papers, standards, and/or IEEE organizational material. The IEEE Thesaurus is a tool to improve and enhance the indexing and retrieval of articles and other material from IEEE periodicals, conferences, standards, and other publications that are made available on IEEE Xplore. It provides a common and consistent language for authors, researchers and online discovery."