Definition of lux in English:


(also lx)


  • The SI unit of illuminance, equal to one lumen per square metre.

    • ‘It is measured in foot-candles or lux.’
    • ‘Lights are maintained at the perfect lux… which makes great conversations and of course the food is as palatable as the views of rhythmic movements of those in waiting.’
    • ‘Professional curators and conservators will look for work elsewhere, and amateurs will be hired who don't care whether light levels are 50 lux or 500 lux.’
    • ‘The light box contains fluorescent light bulbs with a 5,000 lux rating at 8 inches for portable units, or a 10,000 lux rating at 14 inches for countertop units.’
    • ‘Because lux is lumen-per-square-meter we just needed to factor in the surface area to be able to calculate the total lumen output.’
    • ‘Gaelic football matches need a minimum of 250-300 lux output but hurling games need a much higher lux.’
    • ‘However, deep rooms must receive a minimum lux by law hence the large windows and care that there are no balconies overshadowing them.’
    • ‘For a decent ability to see in low light, opt for a unit with a lux of 0.05.’
    • ‘The project will involve increasing the lux value of lights, laying sidewalks, improving traffic junctions, and putting up medians aesthetically’.’
    • ‘Percentage of light reaching the forest floor was measured with a foot candle / lux meter.’
    • ‘The 10,000 lux fluorescent light box is usually used in clinical practice.’
    • ‘Forty patients with SAD were randomized to five weeks of bright light (3,000 lux fluorescent light box for two hours/day) or fluoxetine.’
    • ‘A glazed facade admits sunlight into the space, controlled by a special ‘sandwich’ assembly of perforated metal, colored glass, and microlouvers that limit illuminance to 3.5 lux.’
    • ‘Light boxes for light therapy usually produce between 2,500 lux and 10,000 lux.’
    • ‘Photo settings such as zoom, color tone, self-timer and a high lux flash turn snapping pictures into an art.’
    • ‘These lighting technologies were concomitant with the dark that humans lived with, due mainly to their low candle-power or lux.’
    • ‘By comparison, sunlight gives 10000 lux on a cloudy day, and 80000 lux (at the Equator) on a sunny day.’
    • ‘Four of the markers tested activated at illuminance levels over 100 lux.’
    • ‘For normal keyboard work, most people find a reading of 400 lux comfortable.’
    • ‘The devices are about the size of a computer monitor and use 10,000 - lux fluorescent bulbs, projecting 20 times the brightness of an average lighted room - still dimmer than full sunlight.’


Late 19th century: from Latin, literally ‘light’.