|Origin:||bi- + -illion (as in million)|
bil‧lion plural billion or billions
the number 1,000,000,000:
The final cost could be as much as one billion dollars.
two/three/four etc billion
3.5 billion years ago
Overseas debt is a staggering £16 billion.
billions of pounds/dollars etc
Airlines have lost billions of dollars.
an extremely large number of things or people
A billion stars shone in the night sky.
billions of something
There are billions of things I want to say.
3HMN British English old use
the number 1,000,000,000,000
—billionth noun [countable]