Tourism can be domestic or international, and international tourism has both incoming and outgoing implications on a country's balance of payments. Today, tourism is a major source of income for many countries, and affects the economy of both the source and host countries, in some cases being of vital importance.
Tourism suffered as a result of a strong economic slowdown of the late-2000s recession, between the second half of 2008 and the end of 2009, and the outbreak of the H1N1 influenza virus, but slowly recovered. International tourism receipts (the travel item in the balance of payments) grew to US$1.03 trillion (740 billion) in 2011, corresponding to an increase in real terms of 3.8% from 2010. International tourist arrivals surpassed the milestone of 1 billion tourists globally for the first time in 2012, emerging markets such as China, Russia and Brazil had significantly increased their spending over the previous decade. The ITB Berlin is the world's leading tourism trade fair.
The word tourist was used in 1772 and tourism in 1811. It is formed from the word tour, which is derived from Old English turian, from Old French torner, from Latin tornare; 'to turn on a lathe,' which is itself from Ancient Greek tornos (); 'lathe'.
Tourism is an important, even vital, source of income for many regions and countries. Its importance was recognized in the Manila Declaration on World Tourism of 1980 as "an activity essential to the life of nations because of its direct effects on the social, cultural, educational, and economic sectors of national societies and on their international relations."
Tourism brings in large amounts of income into a local economy in the form of payment for goods and services needed by tourists, accounting for 30% of the world's trade of services, and 6% of overall exports of goods and services. It also creates opportunities for employment in the service sector of the economy associated with tourism.
The service industries which benefit from tourism include transportation services, such as airlines, cruise ships, and taxicabs; hospitality services, such as accommodations, including hotels and resorts; and entertainment venues, such as amusement parks, casinos, shopping malls, music venues, and theaters. This is in addition to goods bought by tourists, including souvenirs.
In 1936, the League of Nations defined a foreign tourist as "someone traveling abroad for at least twenty-four hours". Its successor, the United Nations, amended this definition in 1945, by including a maximum stay of six months.
In 1941, Hunziker and Kraft defined tourism as "the sum of the phenomena and relationships arising from the travel and stay of non-residents, insofar as they do not lead to permanent residence and are not connected with any earning activity." In 1976, the Tourism Society of England's definition was: "Tourism is the temporary, short-term movement of people to destinations outside the places where they normally live and work and their activities during the stay at each destination. It includes movements for all purposes." In 1981, the International Association of Scientific Experts in Tourism defined tourism in terms of particular activities chosen and undertaken outside the home.
In 1994, the United Nations identified three forms of tourism in its Recommendations on Tourism Statistics:
Domestic tourism, involving residents of the given country traveling only within this country
Inbound tourism, involving non-residents traveling in the given country
Outbound tourism, involving residents traveling in another country
The terms tourism and travel are sometimes used interchangeably. In this context, travel has a similar definition to tourism, but implies a more purposeful journey. The terms tourism and tourist are sometimes used pejoratively, to imply a shallow interest in the cultures or locations visited. By contrast, traveler is often used as a sign of distinction. The sociology of tourism has studied the cultural values underpinning these distinctions and their implications for class relations.