- Capitalism: The economic system that dominated the countries involved in the war, with its emphasis on private ownership and profit-making.
- Colonialism: The domination of one country over another, often for the purpose of exploiting the latter's resources.
- Imperialism: The policy of extending a country's power and influence over other countries, often through colonization or military conquest.
- Nationalism: The belief that one's nation is superior to others and should be independent from foreign control.
- Militarism: The glorification of the military and the arms race that developed among the major powers in the years leading up to the war.
- Socialism: The political and economic doctrine that calls for collective ownership of the means of production and distribution of goods and services, as opposed to capitalism.