sun protection factor

noun

|Updated on: 4 Jul 2018

Definition of sun protection factor

: a number assigned to a sunscreen that is the factor by which the time required for unprotected skin to become sunburned is increased when the sunscreen is used —abbreviation SPF

See sun protection factor defined for English-language learners

Recent Examples of sun protection factor from the Web

Lotions, foams and sprays that prevent sunburn are tested at 2 milligrams per square centimeter of skin to determine the sun protection factor, or SPF.

— jo craven mcginty, WSJ, "The Burning Question: How Much Sunscreen?," 29 June 2018
Choose sunscreen that is broad-spectrum (blocks UVB and UVA rays) with a sun protection factor (SPF) of at least 30.

— katy mullens, md, USA TODAY, "Ask a Doc: How do I keep my newborn safe from the summer heat and sunshine?," 12 June 2018
Legitimate sunscreens are made in a wide range of sun protection factor values, also known as SPF values, and are over-the-counter drugs that come in many forms.

— NBC News, "Sunscreen pills are fake medicine, FDA says," 23 May 2018
Typically, the first line of business is to decide on your level of SPF, or sun protection factor.

— CNN Underscored, "Do your skin a favor with this top-rated sunscreen," 1 Nov. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sun protection factor.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.