Definition of Billion

Noun

• the number that is represented as a one followed by 9 zeros
  - one thousand million - 1000000000
• a very large indefinite number (usually hyperbole)
  "there were millions of flies"
  million trillion zillion jillion gazillion
• 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
  - one million million - 1000000000000

Adjective

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

• Scrabble® score of the billion (9)
• Word Chums® score of the billion (13)
• Words With Friends® score of the billion (13)