Outdoor Lighting Glossary

Come across a lighting word you aren't sure of? Completely new to the world of lighting? We feel your pain! Here you will find a collection of terms and concepts that should help to make your life easier.

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Select the first letter of the word from the list above to jump to appropriate section of the glossary.

UL - Underwriters Laboratory. An independent organization whose responsibilities include rigorous testing of electrical products. When products pass these tests, they can be labeled (and advertised) as "UL listed." UL tests for product safety only.

Ultraviolet Light (UV) - Light that is shorter in wavelength and higher in frequency than visible violet light (literally beyond the violet light).

Underwriters Laboratory - Commonly referred to as "UL". An independent organization whose responsibilities include rigorous testing of electrical products. When products pass these tests, they can be labeled (and advertised) as "UL listed." UL tests for product safety only.

Uniformity - On a given plane. A measure of the variation of illuminance over the plane expressed as either 1. The ratio of the minimum to the maximum illuminance. 2. The ratio of the minimum to the average illuminance.