WWI Vocabulary Nationalism pride in one’s country Militarism (arms race) a competition between countries to see who can create the most powerful weapons. System of Alliances when many alliances are made at the same time. Imperialism building an empire by taking over other countries. colonies a country or a region whose government is controlled by another distant country. empire a group of nations, territories or people ruled by a single authority, especially an emperor or empress trigger cause an event or events that over time lead to a reaction. alliance an agreement between countries to help each other in time of need. trigger an event that creates an immediate reaction.