Colonialism

Definitions
1. Colonialism is the establishment, maintenance, acquisition and expansion of colonies in one territory by people from another territory. Colonialism is a process whereby sovereignty over the colony is claimed by the metropole and the social structure, government, andeconomics of the colony are changed by colonists - people from the metropole. Colonialism is a set of unequal relationships: between the metropole and the colony, and between the colonists and the indigenous population. (http://en.wikipedia.org/wiki/Colonialism)
2.A political-economic phenomenon whereby various European nations explored, conquered, settled, and exploited large areas of the world. (http://www.britannica.com/EBchecked/topic/126237/colonialism-Western)
Explanation:
A policy where a nation maintains control over foreign dependencies
Metaphor
Colonialism is like being a parent or a boss. The Mom or dad take care of the kids and own what the kids have. The boss owns the buisness and the workers help the boss, but the boss is still in control.