Frankfurt am Main, commonly known as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2011 population of 695,624. The urban area had an estimated population of 2,300,000 in 2010. The city is at the centre of the larger Frankfurt Rhine-Main Metropolitan Region which has a population of 5,600,000 and is Germany's second-largest metropolitan region.
 
Frankfurt is the financial and transportation centre of Germany and the largest financial centre in continental Europe. It is seat of the European Central Bank, the German Federal Bank, the Frankfurt Stock Exchange and the Frankfurt Trade Fair, as well as several large commercial banks, e.g. Deutsche Bank, Commerzbank and DZ Bank. Frankfurt Airport is one of the world's busiest international airports, Frankfurt Central Station is one of the largest terminal stations in Europe, and the Frankfurter Kreuz is one of the most heavily used Autobahn interchanges in Europe. Frankfurt lies in the former American Occupation Zone of Germany, and it was formerly the headquarters city of the U.S. Army in Germany.
 
Frankfurt is an international centre for finance, commerce, culture, transport, education and tourism. It is therefore considered an alpha world city as listed by the Loughborough University group's 2010 inventory. It was ranked 10th among global cities by the Global Power City Index 2011, 11th by the Global City Competitiveness Index 2012 and 8th among international financial centers by the International Financial Centers Development Index 2011.
 
In 2011, the human-resource-consulting firm Mercer ranked Frankfurt as seventh in its annual "Quality of Living" survey of cities around the world. According to The Economist cost of living survey, Frankfurt is Germany’s most expensive city, and the 10th most expensive in the world.

The three major pillars of Frankfurt's economy are finance, transport and trade fairs.
 
Frankfurt has been Germany's financial centre for centuries and it is the home of a number of major banks and brokerages. The Frankfurt Stock Exchange (Frankfurter Wertpapierborse) is by far Germany's largest, and is one of the world's most important. Frankfurt is also the seat of the European Central Bank (Europaische Zentralbank) which sets monetary policy for the Eurozone, consisting of 17 European Union member states that have adopted the euro (€) as their common currency and sole legal tender, and of the German Federal Bank (Deutsche Bundesbank). In 2010, 63 national and 152 international banks had their registered offices here including the headquarters of the major German banks, notably Deutsche Bank and Commerzbank, as well as 41 representative offices of international banks.
 
The importance of Frankfurt as a financial center is rising in recent years. Indications are the establishment of the European supervisory authority for insurance EIOPA (European Insurance and Occupational Pensions Authority) and the installation of the EU system risk-Council, the European authority for the early detection, prevention and management of systemic risks within the financial market in the EU.
 
Frankfurt has an excellent transportation infrastructure: Frankfurt Airport (Flughafen Frankfurt am Main) is the third busiest airport by passenger traffic in Europe and is the main hub for Germany's flag carrier Lufthansa, the largest airline in Europe. The airport is close to the Frankfurter Kreuz (Autobahn interchange) where two of the most heavily used motorways in Europe, Bundesautobahn 3 in west-east-direction and Bundesautobahn 5 in north-south-direction, meet. In addition, Frankfurt has three railway stations for high-speed ICE trains: Frankfurt Central Station (Frankfurt Hauptbahnhof), Frankfurt South Station (Frankfurt Südbahnhof) and Frankfurt Airport long-distance Station (Frankfurt Flughafen Fernbahnhof). Frankfurt is the busiest junction operated by Deutsche Bahn, the German national railway company, with 342 daily trains to domestic and European destinations.
 
Frankfurt Trade Fair (Messe Frankfurt) is the third largest trade fair in the world with a total area of 578,000 square metres (6,221,540 square feet). It has ten halls with a total of 321,754 square meters (3,463,331 square feet) of exhibition space and 96,078 square metres (1,034,175 square feet) of outdoor area more available. Many large trade fairs are held in Frankfurt each year, notably the Frankfurt Motor Show (Internationale Automobil-Ausstellung - IAA), the world's largest motor show, the Frankfurt Book Fair (Frankfurter Buchmesse), the world's largest book fair, and Musikmesse, the world's largest music fair.
 
Frankfurt is also home to many cultural and educational institutions including the Johann Wolfgang Goethe University and the Frankfurt University of Applied Sciences, many museums (e.g. Stadel, Naturmuseum Senckenberg, Goethe House), and two major botanical gardens, the Palmengarten, which is Germany's largest, and the Botanical Garden of the Goethe University.
 
A unique feature of Frankfurt is its significant number of skyscrapers in the city center which form the Frankfurt skyline. Frankfurt is one of only a few cities in the European Union that have such a skyline, the others being London, Warsaw, Madrid, Rotterdam and La Defense in the outer Paris region. Because of the city's skyline, Germans sometimes humorously refer to Frankfurt am Main as "Mainhattan".

Name
Frankonovurd (in old high German language) or Vadum Francorum (in Latin language) were the first names mentioned in written records from 794. It transformed to Frankenfort during the Middle Ages and then to Franckfort and Franckfurth in Modern history. At the beginning of the 19th century the spelling of Frankfurt was widely established. The name affix "am Main" is used regularly since the 14th century.
 
In English, the city's full name of Frankfurt am Main translates to "Frankfurt on the Main" (pronounced like English mine or German mein). Frankfurt is located on an ancient ford (German: Furt) on the Main river. As a part of early Franconia, the inhabitants were the early Franks, thus the city's name reveals its legacy as being "the ford of the Franks on the Main river".
 
Among English speakers, the city is commonly known simply as Frankfurt, though Germans occasionally call it by its full name when it is necessary to distinguish it from the other (significantly smaller) German city called Frankfurt in the federated state of Brandenburg, Frankfurt (Oder) on the Polish border.
 
The common abbreviations for the city, which are primarily used in railway services and on road signs, are Frankfurt (Main), Frankfurt (M), Frankfurt a.M., Frankfurt/Main or Frankfurt/M. The common acronym for the city is Ffm or FFM.
 
The older English spelling of Frankfort is now rarely seen.