NCIt definition : A photoprotective topical substance for the skin that helps protect the skin against
harmful UV radiation from the sun.;
Alternative definition : NCI-GLOSS: A substance that helps protect the skin from the sun's harmful rays. Sunscreens
reflect, absorb, and scatter both ultraviolet A and B radiation to provide protection
against both types of radiation. Using lotions, creams, or gels that contain sunscreens
can help protect the skin from premature aging and damage that may lead to skin cancer.;