plural billion or billions
1
: the number 1,000,000,000 : one thousand million
a/one/two billion (of them)
a hundred billion = 100 billion
several billion (of them) = (less commonly) several billions (of them)
hundreds of billions (of them)
a billion and one [=1,000,000,001]
a billion and a half = 1.5 billion [=1,500,000,000]
The company is worth billions. [=worth billions of dollars, pounds, euros, etc.]
2
: a very large amount or number
We could see a billion stars in the sky.
I've heard that excuse a billion times before. [=many, many times before]
—often pluralWe could see billions of stars.
billions and billions of stars
3
British, old-fashioned
: the number 1,000,000,000,000 : trillion
Cite this Entry
“Billion.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/billion. Accessed 24 Jun. 2026.
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