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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t
- track lighting
- traffic beams
- train
- transient adaptation factor, TAF
- transillumination
- transition lighting
- translucent insulating panels
- translucent medium
- transmission
- transmissometer
- transmittance (of a medium)
- transparent medium
- transverse light distribution
- transverse roadway line (TRL)
- trichromacy
- tristimulus values of a light, X,Y,Z
- troffer
- troland
- Troxler effect
- tube
- tubular daylighting device (TDD)
- tunable lighting
- tunable white
- tungsten-halogen lamp
- turn-signal operating unit
- twofer
- two-K
u
- U-factor
- ultraviolet germicidal irradiation (UVGI)
- ultraviolet germicidal lamp
- ultraviolet hazard function
- ultraviolet lamp
- ultraviolet radiation
- ultraviolet subdivisions
- unified glare rating, UGR
- uniform chromaticity scale diagram (UCS)
- unilateral sidelighting
- unit (lighting equipment)
- units of luminous exitance
- units of wavelength
- univariance
- unrecoverable light loss factor
- upper (driving) beams
- upward component
- U.S. Customary System (USCS, formerly English) unit of luminance
- useful daylight illuminance (UDI)
v
- vacancy sensor
- vacuum lamp
- valance
- valance lighting
- value
- vapor-tight luminaire
- VASIS
- veiling brightness
- veiling luminance
- veiling reflection
- venetian blinds
- vertical blinds
- vertical plane of a searchlight
- vertical shadow angle
- very short flashes
- view window
- visibility
- visibility level, VL
- visibility (meteorological)
- visibility performance criteria function, VL8
- visibility reference function, VL1
- visible transmittance
- vision
- visual acuity
- visual angle
- Visual Approach Slope Indicator System (VASIS)
- visual comfort probability, VCP
- visual field
- visual perception
- visual performance
- visual photometer
- visual range (of a light or object)
- visual signal
- visual surround
- visual task
- visual task evaluator (VTE)
- visual threshold in point vision
- voltage to luminaire factor
w
- wall direct radiation coefficient, WDRC
- wall pocket
- wall reflected radiation coefficient, WRRC
- warm-up time
- wash
- Weber's fraction
- wide-angle diffusion
- wide-angle luminaire
- width line
- Wien displacement law
- Wien radiation law
- window
- window sash
- window shades
- wing clearance lights
- working standard