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

Kalshi requires users to give their address, at least part of their Social Security number, their phone number, date of birth and identity documentation.

From The Wall Street Journal • Jun. 9, 2026

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

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

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

From The Wall Street Journal • Mar. 20, 2026

And in the blank for Social Security number he’d put down, “228-31-6704.”

From "Into the Wild" by Jon Krakauer