Dictionary.com
definitions

ultraviolet radiation

Radiation in the part of the electromagnetic spectrum where wavelengths are just shorter than those of ordinary, visible violet light but longer than those of x-rays.

Note

Like infrared radiation, ultraviolet radiation can be detected with special instruments or films. Sunburn is caused by ultraviolet radiation. The ozone layer of the atmosphere of the Earth blocks most of the potentially harmful ultraviolet radiation.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.