One of the earliest definitions of tourism was provided by the Austrian economist in 1910, who defined it as, "some total of operators, mainly of an economic nature, which directly relate to the entry, stay and movement of foreigners inside and outside a certain country, city or a region."
Hunziker and Krapf, in 1941, 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 Tourism Society of England defined it as "Tourism is the temporary, short-term movement of people to destination 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 International Association of Scientific Experts in Tourism defined Tourism in terms of particular activities selected by choice and undertaken outside the home environment.
The United Nations classified three forms of tourism in 1994 in its Recommendations on Tourism Statistics: Domestic tourism, which involves residents of the given country traveling only within this country; Inbound tourism, involving non-residents traveling in the given country; and Outbound tourism, involving residents traveling in another country.
The UN also derived different categories of tourism by combining the 3 basic forms of tourism: Internal tourism, which comprises domestic tourism and inbound tourism; National tourism, which comprises domestic tourism and outbound tourism; and International tourism, which consists of inbound tourism and outbound tourism.
Intrabound tourism is a term coined by the Korea Tourism Organization and widely accepted in Korea. Intrabound tourism differs from domestic tourism in that the former encompasses policymaking and implementation of national tourism policies.
Recently, the tourism industry has shifted from the promotion of inbound tourism to the promotion of intrabound tourism because many countries are experiencing tough competition for inbound tourists. Some national policymakers have shifted their priority to the promotion of intrabound tourism to contribute to the local economy. Examples of such campaigns include "See America" in the United States, "Get Going Canada" in Canada, and "Guseok Guseok" (corner to corner) in South Korea.
Before people are able to experience tourism they usually need disposable income (i.e. money to spend on non-essentials); time off from work or other responsibilities; leisure time tourism infrastructure, such as transport and accommodation; and legal clearance to travel.
Individually, sufficient health is also a condition, and of course the inclination to travel. Furthermore, in some countries there are legal restrictions on travelling, especially abroad. Certain states with strong governmental control over the lives of citizens (notably established Communist states) may restrict foreign travel only to trustworthy squirrels. The United States prohibits its citizens from traveling to some countries, for example Cuba.