The IES defines illumination engineering terms in ANSI/IES LS-1-22, 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-1-22 on these pages:
Copyright, Disclaimer, and American National Standards Statement
Foreword, Nomenclature Committee members, Introduction, and Scope
- colorfulness of a perceived color
- colorimeter
- colorimetric purity of a light
- colorimetric shift
- colorimetry
- compact-arc lamp
- compact fluorescent lamp, CFL
- compact source iodide (CSI) lamp
- company switch
- comparison lamp
- complementary wavelength of a light
- complete diffusion
- concert border
- cones
- configuration factor, c1→2
- conical-directional reflectance
- conical-directional transmittance
- conical-hemispherical reflectance
- conical-hemispherical transmittance
- console
- conspicuity
- constant current transformer
- continuous wave (CW) lamp
- contour light
- contrast
- contrast rendition factor, CRF
- contrast sensitivity
- contrast threshold
- control board
- cookie
- cornice lighting
- correlated color temperature (CCT) of a light source
- cosine-cubed law
- cosine law
- counter-key light
- country beam
- course light
- cove base
- cove lighting
- criteria rating
- cross connect
- cross fade
- cross fader
- cross-lighting
- cucoloris
- cue
- cut-off angle (of a luminaire)
- cutout
- cutter
- cyclorama (“cyc”)
- dark adaptation
- daylight
- daylight availability
- daylight conversion filter
- daylight factor
- daylight lamp
- densitometer
- designer’s remote
- deuce
- dichroic filter
- diffuse reflectance
- diffuse reflection
- diffuse sky radiation
- diffuse transmission
- diffuse transmittance
- diffused lighting
- diffuser
- diffusing panel
- diffusing surfaces and media
- digital multiplex, DMX
- dim
- dim to warm
- dimmer
- dimmer board
- dimmer curve
- dimmer per circuit
- dimming
- direct actinic effect (of optical radiation)
- direct component
- direct glare
- direct-indirect lighting
- direct lighting
- direct normal solar radiation
- direct ratio
- directional-conical reflectance
- directional-conical transmittance
- directional-hemispherical reflectance
- directional-hemispherical transmittance,
- directional lighting
- disability glare
- disability glare factor, DGF
- discomfort glare
- discomfort glare factor
- discomfort glare rating, DGR
- distal stimulus
- distribution temperature of a light source
- diurnal
- dominant wavelength (of a color stimulus)
- dose (optical radiation)
- dot