RhymeZone: billion definitions

Definitions of billion:

noun: the number that is represented as a one followed by 9 zeros
noun: 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
adjective: denoting a quantity consisting of one thousand million items or units in the United States
adjective: denoting a quantity consisting of one million million items or units in Great Britain