Colonialism: This is a policy or practice where a powerful country extends its influence over other areas or people, often establishing settlements and exploiting resources.
Imperialism: This refers to a policy or ideology where a nation extends its power by acquiring territories. It may also include the exploitation of these territories for economic gain.
Settlements: These are places, typically with previously uninhabited land, where communities are established. In this context, it refers to communities established by Europeans in America.