Advanced Lighting Guidelines Glossary
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ALL A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0-9
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Definition
Absolute Photometry Photometry is the measurement of the properties of light, particularly intensity. Absolute photometry, used for conventional lamps and luminaires with… More »
Action Spectrum The magnitude of a given stimulus required to produce a fixed physiological response, plotted against wavelength. The action spectrum reveals… More »
Adaptation The process by which the retina becomes accustomed to more or less light than it was exposed to during an… More »
Adaptation luminance The luminance to which the visual system is assumed to be adapted. In practice, this is usually taken to be… More »
Adaptive compensation Control strategy in which light levels are reduced during evening hours to accommodate human lighting preferences at night and save… More »
Altitude The vertical angular distance of a point in the sky above the horizon. Altitude is measured positively from the horizon… More »
Amalgam An alloy of mercury with other metals. Some CFLs use a mercury amalgam rather than standard mercury. An amalgam keeps… More »
Ambient lighting Lighting throughout an area that produces general illumination that may or may not be uniform. Original Chapter Source: Luminaires Provided… More »
ANSI American National Standards Institute Original Chapter Source: Policies & Programs More »
Aperture In buildings, an aperture is an opening, such as a window or a skylight, that allows daylight to enter the… More »
Application efficiency A lighting design metric that looks at the fraction of of light (lumens) at the point of use (visual task)… More »
Aqueous humor The transparent, watery fluid between the cornea and the lens of the eye. Original Chapter Source: Health & Performance Provided… More »
ASHRAE American Society of Heating, Refrigerating, & Air-Conditioning Engineers Original Chapter Source: Policies & Programs More »
Atrium A multistoried space within a building that allows daylight to illuminate the adjacent interior spaces typically through a large overhead… More »
Auxiliaries Electrical devices that provide proper voltage to ignite light sources and regulate current during normal operation. Examples include ballasts, transformers… More »
Azimuth The horizontal angular distance between the vertical planes containing two points in the sky. The azimuth of a single point… More »
ALL A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0-9

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