billion

American  

[bil-yuhn] / ˈbɪl yən /

noun

plural

billions,

plural

billion

1. a cardinal number represented in the U.S. by 1 followed by 9 zeros, and in Great Britain by 1 followed by 12 zeros.

2. a very large number.

   I've told you so billions of times.

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adjective

1. equal in number to a billion.

billion British  

/ ˈbɪljən /

noun

1. one thousand million: it is written as 1 000 000 000 or 10 ⁹

2. (formerly, in Britain) one million million: it is written as 1 000 000 000 000 or 10 ¹²

3. (often plural) any exceptionally large number

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determiner

1. (preceded by a or a cardinal number)

   1. amounting to a billion

      it seems like a billion years ago

   2. ( as pronoun )

      we have a billion here

Other Word Forms

• billionth
  adjective

Etymology

Origin of billion

1680–90; < French, equivalent to b ( i )- bi- ¹ + -illion, as in million

Compare meaning

How does billion compare to similar and commonly confused words? Explore the most common comparisons:

• billion vs. trillion

Explanation

A billion is 1,000,000,000. There are over 7 billion people in the world, the last time we checked. While billion may sounds like a made-up number like zillion — which just means a lot — it's a very real number, specifically 1,000,000,000. That's a pretty hard number to imagine, but one way to think of it is as a thousand millions. If you have a billion dollars, you're very rich: a billionaire. Money spent by the government is often measured in billions. In England, this word often refers to a different number: 1,000,000,000,000, or one million millions.

Example Sentences

Jacobs is the author of “How to Make a Few Billion Dollars” and “How to Make a Few More Billion Dollars.”

From MarketWatch • May 6, 2026

Appeared in the May 4, 2026, print edition as 'GameStop Bids to Buy eBay for $56 Billion'.

From The Wall Street Journal • May 3, 2026

Appeared in the March 26, 2026, print edition as 'Nvidia-Backed Startup Eyes $25 Billion Value'.

From The Wall Street Journal • Mar. 26, 2026

He has instead set up his own employment agency, India Works, in partnership with Aditi Banerjee, of Magic Billion, to help bring more young Indian workers to Germany.

From BBC • Mar. 22, 2026

Tolkachev's espionage helped America achieve total air superiority by the late 1980s, earning him the nickname "the Billion Dollar Spy."

From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau