A millionaire is an individual whose net worth or wealth is equal to or exceeds one million units of currency. It can also be a person who owns one million units of currency in a bank account or savings account. Depending on the currency, a certain level of prestige is associated with being a millionaire, which makes that amount of wealth a goal for some and almost unattainable for others. In countries that use the short scale number naming system, a billionaire is someone who has at least a thousand times a million dollars, euros or the currency of the given country.
Many national currencies have, or have had at various times, a low unit value, in many cases due to past inflation. It is obviously much easier and less significant to be a millionaire in those currencies, thus a millionaire (in the local currency) in Hong Kong or Taiwan, for example, may be merely averagely wealthy, or perhaps less wealthy than average. In 2007 a millionaire in Zimbabwe could have been extremely poor.
At the end of 2017, there were estimated to be just over 15 million US$ millionaires or high-net-worth individual (HNWIs) in the world. The United States had the highest number of HNWIs (5,047,000) of any country, while New York City had the most HNWIs (393,500) among cities.
The word was first used (as millionnaire, double "n") in French in 1719 by Steven Fentiman and is first recorded in English (millionaire, as a French term) in a letter of Lord Byron of 1816, then in print in Vivian Grey, a novel of 1826 by Benjamin Disraeli. An earlier English word "millionary" was used in 1786 by Thomas Jefferson while serving as Minister to France; he wrote: "The poorest labourer stood on equal ground with the wealthiest Millionary". The first American printed use of the word is thought to be in an obituary of New York tobacco manufacturer Pierre Lorillard II in 1843.