What is the definition of mass tourism?

Mass tourism is the act of visiting a destination with large amounts of people at one time, and the study of the effect that large amounts of people can have on a particular destination, or on a particular destination which has been over-exposed by single tourists having been there repeatedly. These tourist also help other businesses such as telecommunication services.

It also means:

Traditional, large scale tourism commonly, but loosely used to refer to popular forms of leisure tourism pioneered in southern Europe, the Caribbean, and North America in the 1960s and 1970s