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

---

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

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

From The Wall Street Journal • Mar. 20, 2026

They both say Craig Gilner, and have my Social Security number and a bar code on them.

From "It’s Kind of a Funny Story" by Ned Vizzini