What term refers to the build-up of military forces before World War I?

The term that refers to the build-up of military forces before World War I is militarism. This concept emphasizes the importance and influence of military power in national policy and governance. Before the outbreak of the war, several European nations significantly increased their military capabilities and stockpiled weapons, contributing to a tense atmosphere of competition and fear among countries.

Militarism not only involved expanding the size of armies and navies but also fostering a culture that celebrated military service and strategy as vital to national strength. This arms race can be seen in the context of European powers vying for dominance and influence, leading to a cascading series of alliances and conflicts which ultimately culminated in the war.

Imperialism, while a related concept, refers primarily to the expansion of empires and the control over territories, rather than the specific military build-up. Nationalism relates to a strong identification with and pride in one's nation, often leading to competition with other nations, but it does not directly denote military preparation. Colonialism focuses on the establishment of settlements in other lands and the domination of those areas, which is distinct from the militaristic preparations before the war.