Sunscreen (noun)

1. A lotion, cream, or other substance that is applied to the skin to protect it from the sun's harmful rays.
2. A product that is used to protect the skin from the sun's ultraviolet (UV) rays.

Origin:

From sun + screen.

Examples:

1. I always wear sunscreen when I go to the beach.
2. It is recommended to apply sunscreen every 2 hours.
3. She used a high SPF sunscreen to protect her fair skin.
4. The sunscreen needs to be reapplied after swimming or sweating.
5. Sunscreen is important to prevent skin cancer.