On October 31st the UN will dub a newborn the world's 7 billionth living person.
From the economist.com
In a kitchen you're not just multitasking, you're multitasking to the billionth.
From the dinersjournal.blogs.nytimes.com
The measurement is sensitive to movements as small as one-billionth of a meter.
From the sciencedaily.com
As if we needed more proof, Apple moved its billionth app earlier this afternoon.
From the techcrunch.com
All you have to do to win is be lucky enough to download the 10 billionth song.
From the abcnews.go.com
By the time you read this article, the seven billionth baby will no doubt be born.
From the telegraph.co.uk
A nanometer is one billionth of a meter, making each string about 150 atoms thick.
From the sciencedaily.com
Apple started the official countdown two weeks ago to its one billionth app served.
From the abcnews.go.com
The 6 billionth, Adnan Nevic, was born on October 12th 1999 in Sarajevo, in Bosnia.
From the economist.com
More examples
Position 1,000,000,000 in a countable series of things
The ordinal number of one billion in counting order
One-billionth: one part in a billion equal parts
One billionth is the reciprocal of a billion, which means it has one of two definitions depending on whether the long scale or short scale definition is being used.