sun protection factor n.
The ratio of the minimal ultraviolet dose required to produce erythema with and without a sunscreen; a measure of the degree to which a sunscreen protects the skin from ultraviolet radiation, the higher the number the greater degree of protection.
|sun protection factor
A measure, expressed numerically, of the degree to which a preparation containing sunscreen protects the skin from ultraviolet rays. The higher the value, the greater the level of protection from sun damage to the skin.