UV stopper (5)

I believe the answer is:

ozone

(Other definitions for ozone that I've seen before include "Layer that protects against ultraviolet rays" , "Gas forming screen against ultraviolet radiation in the stratosphere" , "That precious layer" , "Sea air; toxic gas" , "A poisonous gas; seaside air" .)

I've seen this clue in the King Feature Syndicate.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.