UVB 
(y′vē′bē)
(y′vē′bē)n.
Ultraviolet radiation that is found in sunlight, has a wavelength between 290 and 320 nanometers, and can cause damage to the skin including sunburn, tanning, premature aging, and cancer.
[u(ltra)v(iolet) B (the letter B being used to designate the second of the categories based on wavelength in which ultraviolet radiation is classified).]