Ultraviolet Rays

**Definition:** That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.

**Tree numbers:** - G01.358.500.505.650.891 - G01.590.540.891 - G01.750.250.650.891 - G01.750.750.659 - G01.750.770.578.891 - G16.500.275.063.725.525.600 - G16.500.750.775.525.600 - N06.230.300.100.725.525.600

**Synonyms:** - Actinic Rays - Ultraviolet Light - UV Light - Ultra-Violet Rays