num
billion
BIHL-yuhn
num
1
A thousand million: 1,000,000,000 (10⁹), the standard modern meaning.
"The company is now worth over a billion dollars."
2
An extremely large, unspecified number.
"I've told you a billion times to lock the door."
How to Use Billion
Learner’s notesIn plain EnglishThe number 1,000,000,000, or loosely, "a huge number."
UK vs US
The old British "long scale" billion (10¹²) is obsolete; UK and US now both use 10⁹.
Common pairings
a billion dollars
billions of people
Word Forms
billions plural
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Etymology
From French billion, formed from bi- ("two") plus -illion. Older British usage once meant a million million (10¹²), but the "thousand million" meaning is now standard worldwide.