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sun protection factor

American

noun

SPF.

sun protection factor Scientific

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.

Etymology

Origin of sun protection factor

First recorded in 1975–80

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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

Dermatologists recommend using a minimum sun protection factor of 30.

From New York Times • Jul. 5, 2022

Shelves that had been stocked with bottles claiming SPF, or sun protection factor, ratings of 30 now have products that trumpet SPF ratings of 55, 70, even 110-plus.

From Seattle Times • Jun. 19, 2010

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

From Time Magazine Archive

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023