The term 'ultraviolet ray blocker' can be summarized by the crossword solution of 'OZONE'. OZONE is a naturally occurring gas in the Earth's atmosphere that absorbs ultraviolet radiation from the sun. It is an important part of the Earth's protective OZONE layer, which helps to protect us from the harmful effects of UV radiation. OZONE is also used in many products, such as sunscreens and sunglasses, to help block out UV rays.