billion

American  

[bil-yuhn] / ˈbɪl yən /

noun

billions plural

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

The US multinational maker of Post-it and Scotch tape also reached a $10 billion settlement in the United States in 2023 over contamination of water supplies.

From Barron's • May 28, 2026

The effort aligns with the Pentagon’s $1.1 billion Drone Dominance program, aiming for 300,000 low-cost attack drones by the end of 2027.

From The Wall Street Journal • May 28, 2026

Costco is expected to report fiscal third-quarter earnings of $4.98 per share, a 16.3% increase, on $69.68 billion in revenue.

From Barron's • May 28, 2026

The effort dovetails with the aims of the Pentagon’s Drone Dominance program, a $1.1 billion initiative to amass an arsenal of around 300,000 low-cost attack drones by the end of 2027.

From The Wall Street Journal • May 28, 2026

“He’s also granted free lifetime claw trimming. And he planted a billion new trees to replace the ones you burned in the last war.”

From "Klawde: Evil Alien Warlord Cat" by Johnny Marciano and Emily Chenoweth