Colonization, (or Colonisation in British English), occurs whenever any one or more species populate an area. The term, which is derived from the Latin colere, "to inhabit, cultivate, frequent, practice, tend, guard, respect," originally related to humans. However, 19th century biogeographers dominated the term to describe the activities of birds, bacteria, or plant species. Human colonization is a narrower category than the related concept of colonialism, because whereas colonization refers to the establishment of settler colonies, trading posts, and plantations, colonialism deals with this and the ruling of new territories' existing peoples.

Modern Colonization

In some cases, expatriate communities do set up permanently in target countries, which is a 'truer' colonization, though in many cases (especially when not gathered into a community) expatriates do not necessarily seek to 'expand their native civilization', but rather to integrate into the population of the new civilization.

Many nations also have large numbers of guest workers who are brought in to do seasonal work such as harvesting or to do low-paid manual labor. Guest workers or contractors have a lower status than workers with visas, because guest workers can be removed at any time for any reason. Many human colonists came to colonies as slaves, so the legal power to leave or remain may not be the issue so much as the actual presence of the people in the new country.