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.
The Big 3 — Verizon , AT & T and T-Mobile — have lost billions in market value since SpaceX announced an acquisition of low-band spectrum last week. — Tobias Burns, CNBC, 13 Oct. 2026 Saudi Arabia spends tens of billions of dollars on defense every year, but is struggling to protect key assets such as airports, refineries and pipelines from missiles and drones fired by Houthi militants from Yemen. — Tim Lister, CNN Money, 13 Oct. 2026 Co-founded by Miami Dolphins owner Stephen Ross, Relevent already is selling billions of dollars of Champions League broadcast and sponsor rights for UEFA in a separate club competitions deal running from 2027 to 2033. — ABC News, 13 Oct. 2026 The money most likely came from Iran, which has supplied Hezbollah with billions of dollars and weapons over decades. — Bassem Mroue, Los Angeles Times, 13 Oct. 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 14 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!