noun
1. : an ultraviolet ray — not used technically
2. : a high-frequency electric discharge from the outer surface of a one-electrode vacuum tube having violet-colored fluorescence and often used in therapeutic treatments
noun
1. : an ultraviolet ray — not used technically
2. : a high-frequency electric discharge from the outer surface of a one-electrode vacuum tube having violet-colored fluorescence and often used in therapeutic treatments
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012