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
- maintenance factor (MF)
- Martingale
- master
- matte
- matte surface
- mean horizontal intensity (candlepower)*
- mean spherical luminous intensity
- mean zonal candlepower
- means of egress
- median life
- memory
- mercury-fluorescent lamp (phosphor mercury lamp)
- mercury lamp
- mesopic vision
- message
- metal halide lamp
- metamerism
- metamers
- meteorological optical range
- midget
- Mie scatter
- minimal perceptible erythema
- minimum erythemal dose
- MIRED
- modeling light
- modulation threshold
- monocular visual field
- motion detector
- mounting height, MH (interior)
- mounting height, MH (roadway)
- multiple-beam headlamp
- Munsell chroma
- Munsell color system
- Munsell hue
- Munsell value