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

In addition, make sure your name, tax year and Social Security number are on the reply.

From The Wall Street Journal • Mar. 20, 2026

That includes a driver’s license number or the last four digits of their Social Security number.

From Los Angeles Times • Jan. 25, 2026

You should not, in most situations, give your children your Social Security number.

From MarketWatch • Dec. 31, 2025

The federal government is seeding these accounts after July 4 with $1,000 for children with a Social Security number who are born between Jan. 1, 2025 and the end of 2028.

From Barron's • Dec. 23, 2025

I made Bryce twenty-two years old and gave him a brand-new Social Security number, an immaculate credit rating, and a bachelor’s degree in Computer Science.

From "Ready Player One: A Novel" by Ernest Cline