Social Security number

American  

[soh-shuhl si-kyoor-i-tee nuhm-ber] / ˈsoʊ ʃəl sɪˈkyʊər ɪ ti ˌnʌm bər /

noun

1. a unique nine-digit number assigned to each U.S. citizen and sometimes also given to resident non-citizens, used by the government for Social Security taxes, program eligibility, etc. SSN

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Etymology

Origin of Social Security number

First recorded in 1935–40

Example Sentences

Babies born from 2025 to 2028 who are American citizens and have a Social Security number are eligible for the seed money.

From Barron's • May 28, 2026

Any child with a Social Security number is eligible for an account, which can grow tax-deferred for decades.

From The Wall Street Journal • May 27, 2026

You’ll need to enter a California driver’s license or identification number or the last four digits of your Social Security number.

From Los Angeles Times • May 1, 2026

A secure portal also beats emailing documents directly to your preparer, since forms often include your Social Security number and other sensitive financial information.

From MarketWatch • Apr. 1, 2026

The Social Security number turned out to be genuine and placed McCandless’s permanent residence in northern Virginia.

From "Into the Wild" by Jon Krakauer