sun protection factor

American  

noun

1. SPF.

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sun protection factor Scientific  

1. 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.

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Etymology

Origin of sun protection factor

First recorded in 1975–80

Example Sentences

The most prominent number on sunscreen bottles is the sun protection factor or SPF.

From BBC • Jun. 30, 2025

Chemical sunscreen also allows for a higher SPF, or sun protection factor, which is a measure of how much UV radiation is needed to cause a sunburn on sunscreen-coated skin versus unprotected skin.

From Scientific American • Sep. 6, 2023

The recall includes all can sizes and all levels of sun protection factor, or SPF.

From Seattle Times • Jul. 14, 2021

The rating, which stands for sun protection factor, is meant to reflect how well a product protects against sunburn, which should also reduce the risk of skin cancer and sun-induced skin aging.

From New York Times • Jun. 29, 2015

But pay attention to the sun protection factor, or spf, rating on the label.

From Time Magazine Archive