DEFINITION of 'Billionaire'

An individual who has assets or a net worth of at least one billion currency units such as dollars, euros or pounds. Each year, Forbes magazine publishes a list of the world's billionaires. When Forbes produced the first list in 1987, there were 140 names on the list. Twenty-five years later, in 2012, the list had grown to 1,226, an all-time high. Twenty-four of the billionaires on the original 1987 list remained on the list for 2012.

BREAKING DOWN 'Billionaire'

According to the 2012 Forbes report, there are billionaires from 58 countries, with the most coming from the United States, Russia and mainland China. As of 2012, some of the world's wealthiest billionaires included Carlos Slim Helu (net worth: $69 billion, source: telecommunications), Bill Gates ($61 billion, Microsoft), Warren Buffett ($44 billion, Berkshire Hathaway) and Bernard Arnault ($41 billion, LVMH).