1
US : a number equal to 1,000 million see Table of Numbers
also, British : a number equal to 1,000 milliard see Table of Numbers
2
: a very large number
billion adjective

Did you know?

How much is a billion? It might depend on whom you ask. Billion was borrowed from French in the late 1600s to indicate the number one million raised to the power of two, or a million million—a number represented by a 1 followed by 12 zeros. However, the French later changed their naming conventions so that a billion became a thousand million (a 1 followed by 9 zeros) and a trillion became a thousand thousand million (or a million million, the old billion). The French have since returned to the older system, but it was this new system that was adopted by American English speakers in the 1800s. In Britain, the newer system has seen increasing use since the 1950s, but the older sense is still sometimes used there as well.

Examples of billion in a Sentence

We could see a billion stars in the sky.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
With annual revenues that can exceed hundreds of billions of dollars, these financial dynasties have made their mark both nationwide and across the globe. — Alex Gurley, PEOPLE, 30 Sep. 2026 The agency advanced billions to Chicago Title Insurance in escrow to acquire detention facilities, according to a Department of Homeland Security spokesperson. — Julia Ingram, CBS News, 29 Sep. 2026 Her government is expected to make billions of dollars in investments linked to the 2030 FIFA World Cup, while seeking to deliver on promises to fight inflation, raise wages and create jobs. — ABC News, 29 Sep. 2026 From 1980 to 1988, the country fought a war with Iraq that killed hundreds of thousands of Iranians and left the state with hundreds of billions of dollars in damage. — Ali Vaez, Foreign Affairs, 29 Sep. 2026 See All Example Sentences for billion

Word History

Etymology

French, from bi- + -illion (as in million)

First Known Use

1801, in the meaning defined at sense 2

Time Traveler
The first known use of billion was in 1801

Browse Nearby Words

Podcast

Cite this Entry

“Billion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/billion. Accessed 1 Oct. 2026.

Kids Definition

1
: a number equal to 1,000 million : 1,000,000,000 see number
2
: a very large number
billion adjective
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster