2 Answers

1 thousand
1,000,000,000    

billion |?bily?n|
cardinalnumber ( pl. billions or (with numeral or quantifying word) same )
the number equivalent to the product of a thousand and a million; 1,000,000,000 or 109: a world population of over 6 billion | half a billion dollars.
• (billions) informal a very large number or amount of something: our immune systems are killing billions of germs right now.
• a billion dollars (or pounds, etc.): the problem persists despite the billions spent on it.
• dated, chiefly Brit.a million million (1,000,000,000,000 or 1012).
DERIVATIVES
billionth |-y?nTH|ordinalnumber
ORIGIN late 17th cent.: from French, from million, by substitution of the prefix bi- ‘two’ for the initial letters.

trillion |?trily?n|cardinalnumber ( pl. trillions or (with numeral) same )a million million (1,000,000,000,000 or 1012).• (trillions) informal a very large number or amount: theyammering of trillions of voices.• dated, chiefly Brit.a million million million (1,000,000,000,000,000,000 or 1018).DERIVATIVEStrillionth |-y?nTH|ordinalnumberORIGIN late 17th cent.: from French, from million, by substitution of the prefix tri- ‘three’ for the initial letters.