billions
n. C / Un. a very large number, specifically thousands of millions. You use this word to talk about huge amounts of money, people, or stars.
n. the cardinal number equal to one thousand million (1,000,000,000). Often used figuratively in the plural to indicate an indefinitely large quantity.
There are billions of stars in the galaxy.
The government spent billions on the new high-speed rail project over the last decade.
Astronomers estimate that there are billions of galaxies in the observable universe, each containing hundreds of billions of stars and potentially even more planets.
When used as a specific number, it is singular and takes no 's' (two billion); when used to mean 'many', it is plural and takes 'of' (billions of people).
five billions dollarsfive billion dollarsWhen a specific number precedes 'billion', the word remains singular and does not take an 's'.