Ultraviolet index. The ultraviolet index or UV Index is an international standard measurement of the strength of sunburn-producing ultraviolet (UV) radiation at a particular place and time. The scale was developed by Canadian scientists in 1992, then adopted and standardized by the UN's World Health Organization and World Meteorological Organization in 1994.
one-quarter-one of four equal parts; a quarter of a pound. fourth part, one-fourth, quarter, quartern, twenty-five percent, fourth. common fraction, simple fraction-the quotient of two integers.
one of the four equal or equivalent parts into which anything is or may be divided: a quarter of an apple; a quarter of a book. 2. a fourth part, especially of one (Â¼). 3. one fourth of a U.S. or Canadian dollar, equivalent to 25 cents. 4. a coin of this value.