This white paper, which was originally published in 2012, was updated to clarify terminology related to daylight responsive controls. NEMA LSD 64 defines terminology related to controls for lighting systems for non-residential and residential applications. The goal of LSD 64 is for NEMA definitions to ultimately be used as the definitive reference for codes, standards, and legislation. This will eliminate the creation of new meanings for already defined terms, will minimize misapplication of controls terminology, and will eliminate the need for customized glossaries and terminology sections. NEMA LSD 64-2014 may be downloaded at no cost on the NEMA website.