scope:

Only the most important quantities and units used in lighting design and illuminating engineering that relate directly to optical radiation, light, and vision are described and defined in this document. The technical words associated with lighting equipment, photometry, lighting calculations, color, and daylighting are defined in other documents in the IES Library, and they rely on an understanding of the material presented in this document. (Refer to ANSI/IES LS-1-22, Lighting Science: Nomenclature and Definitions for Illuminating Engineering² for the locations of the definition of specific words.)

A full nomenclature and many more derived and specialized quantities are also described in the International Lighting Vocabulary, established by the International Commission on Illumination (CIE) and published jointly with the International Electrotechnical Commission.³ More than 900 technical definitions of concepts and quantities are given in English, French, German, and Russian.