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.
In his recent memoir, Newsom describes being divided between his life as the son of an impoverished single mother and the surrogate son of a family with billions in oil industry money. Dan Walters, Mercury News, 15 July 2026 The tens of billions that easily plow into Anthropic and OpenAI, Ryan said, are their own category of investing. Allie Garfinkle, Fortune, 15 July 2026 Al-Zaidi’s visit parallels a trip by Saudi Crown Prince Mohammed bin Salman last November, when the White House announced hundreds of billions of dollars in private and public commitments by the two countries. Lauren Morganbesser, semafor.com, 15 July 2026 Russia is increasingly embroiled in its war with Ukraine and not able to send more aid to an island that already owes their former Cold War patron billions of dollars. Patrick Oppmann, CNN Money, 15 July 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

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Cite this Entry

“Billion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/billion. Accessed 18 Jul. 2026.

Kids Definition

1
: a number equal to 1,000 million : 1,000,000,000 see number
2
: a very large number
billion adjective

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