- The definition of a billion is a thousand millions.
An example of a billion is $1,000,000,000.
billion definition by Webster's New World
- a thousand millions (1,000,000,000)
- Brit. trillion (a million millions)
Origin: French ; from bi-, bi- plush (mi)llion
billion definition by American Heritage Dictionary
- The cardinal number equal to 109.
- Chiefly British The cardinal number equal to 1012.
- An indefinitely large number.
Origin: French, a million million : blend of bi-, second power; see bi-1 and million.
- bilˈlion adjective