Late 19th century (in an earlier sense). From German Reichswehr the conscripted wartime militia in the Russian Empire, German army under the Weimar Republic and the first few years of the Third Reich (1919; earlier used informally to denote German armed forces; earlier in general sense ‘defence of the realm’) from Reichs-, combining form of Reich + Wehr defence, army (Old High German werī, Middle High German were, wer) from the Germanic base of were.