ANSI/IES LS-1-25, Lighting Science: Nomenclature and Definitions for Illuminating Engineering
The IES defines illumination engineering terms in ANSI/IES LS-1-25, is available here online. You can search terms by their first letter using the categories listed in the Categories window, by the first letter of the term in the alphabetical list below, or by typing the term in the search window. You can find the Introduction material for LS-1-25 on these pages:
- Copyright, Disclaimer, and American National Standards Statement
- Preface, Nomenclature Committee members, Introduction, and Scope
- Spectral Parameters Used in Illumination Engineering
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- lamp control
- lamp failure
- lamp lumen depreciation
- lamp position factor
- lamp post
- lamp shielding angle, ϕ
- landing direction indicator
- landing light
- landmark beacon
- laser
- lateral width of a light distribution
- law of reciprocity (Bunsen-Roscoe law)
- LED array or module
- LED control circuitry
- LED die
- LED driver
- LED driver, Class II
- LED lamp, integrated
- LED lamp, non-integrated
- LED light engine
- LED luminaire
- LED package
- LED power source
- LED power supply
- Leko
- lens
- level of illumination
- life of a test lamp
- life performance curve
- life test of lamps
- life test racks
- light
- light adaptation
- light center
- light center length (LCL)
- light emitting diode (LED)
- lighting-cooling index
- lighting effectiveness factor, LEF
- lighting power density (LPD)
- lighting zone (exterior lighting)
- lighting zone (interior lighting controls)
- light lift
- light loss factor (LLF)
- light meter
- lightness (of a perceived patch of surface color)
- light output ratio
- light plot
- light shelf
- light source color
- light source description (for risk group classification)
- light source lumen depreciation, LLD
- light-to-solar-gain ratio
- light trespass
- light well
- linear light
- linear polarization
- Linnebach projector
- loader
- Local Chroma Shift (Rcs,hj)
- Local Color Fidelity (Rf,hj)
- Local Hue Shift (Rhs,hj)
- localized general lighting
- local lighting
- local solar time (LST)
- long-arc lamp
- longitudinal light distribution
- longitudinal roadway line (LRL)
- louvered ceiling
- louver (or louver grid)
- louver shielding angle, θ
- low-bay lighting
- low-e coating
- lower (passing) beams
- low-iron glass
- low-key lighting
- low-pressure mercury germicidal lamp
- low pressure mercury lamp
- low pressure sodium (LPS) lamp
- lumen
- lumen (or flux) method
- lumen-second
- luminaire
- luminaire ambient temperature factor
- luminaire dirt depreciation, LDD
- luminaire efficiency
- luminaire spacing criterion, SC
- luminaire surface depreciation factor
- luminance
- luminance coefficient, q
- luminance coefficient, LC
- luminance contrast
- luminance contrast sensitivity
- luminance difference
- luminance difference threshold
- luminance factor, β
- luminance ratio
- luminance threshold
- luminescence
- luminous ceiling
- luminous efficacy of a source