Definition

1. Cardinal Number:

   • One thousand million (1,000,000,000 or 10⁹): This is the primary meaning in modern English, especially in the United States, Canada, and most of the English-speaking world. It is the standard meaning in finance, science, and general usage.
   • One million million (1,000,000,000,000 or 10¹²): This is the traditional meaning in British English (the "long scale"), though it is now largely archaic. The short scale (thousand million) is now standard in the UK for official and most general purposes.

2. Noun (Informal/Figurative):

   • A very large, indefinite number: Used hyperbolically to emphasize a vast, uncountable quantity.

Usage Examples

• As a cardinal number (10⁹):

  • The company's revenue exceeded five billion dollars last year.
  • It is estimated that there are over seven billion people on Earth.
  • A nanosecond is one billionth of a second.

• As a noun (figurative):

  • I've told you a billion times to clean your room!
  • She has a billion ideas for the new project.

Advanced Usage and Clarification

• Numerical Ambiguity: Historically, the word billion had different values (10⁹ vs. 10¹²). To avoid confusion in critical contexts like contracts or scientific papers, it is advisable to use the unambiguous forms "thousand million" (10⁹) or "million million" (10¹²), or to write the figure numerically (e.g., 1,000,000,000).
• Scale Systems:
  • Short Scale (used in US, UK, and most English-speaking countries): Each new term is 1,000 times the previous (thousand, million, billion, trillion).
  • Long Scale (traditional in parts of Europe): Each new term is 1,000,000 times the previous (million, billion/milliard, trillion).

Variants and Related Words

• Billions (plural noun): An enormous but unspecified number.
  • The stars in the sky number in the billions.
• Billionth (ordinal number/adjective): Constituting number one billion in a sequence; one of a billion equal parts.
  • This is the billionth visitor to our website.
  • A billionth of a meter is called a nanometer.

Synonyms

• Giga- (prefix): Denoting a factor of 10⁹, as in .
• A very large number: A zillion, a gazillion, a multitude, a host (for the figurative sense).

Related Phrases and Idioms

• Thanks a billion!: An informal, emphatic way to say "Thank you very much!"
• One in a billion: Used to describe someone or something exceptionally rare or unique.
  • Her talent is one in a billion.

Adjective

1. denoting a quantity consisting of one million million items or units in Great Britain
2. denoting a quantity consisting of one thousand million items or units in the United States

Noun

1. the number that is represented as a one followed by 9 zeros
2. a very large indefinite number (usually hyperbole)
   • there were millions of flies
3. the number that is represented as a one followed by 12 zeros; in the United Kingdom the usage followed in the United States is frequently seen