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bil·lion (bĭlyən)
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n.
1. The cardinal number equal to 109.
2. Chiefly British The cardinal number equal to 1012.
3. An indefinitely large number.

[French, a million million : blend of bi-, second power; see BI-1 and MILLION.]

billion adj.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.