Colonialism is distinguished from “imperialism” in that imperialism generally refers to the outward-looking role of the metropolitan centre in creating an ideological theory and of ruling another territory. “Colonialism”, on the other hand, is generally invoked to suggest the practice of settling and proceeding to rule over a territory. Therefore, “imperial” is used to describe the centre, “colony” the territory.
In the context of this dictionary and current conversations around decolonisation in museums and wider society, colonialism refers to the European imperial project, and its offshoots in settler societies (e.g. Canada, the USA, Australia, South Africa and New Zealand). Whilst direct colonial rule over parts of the world was a historical project, we continue to live with these inheritances today, both in metropolitan centres and former colonies.
 Edward Said, Culture and Imperialism, (London: Chatto & Windus, p. 9).