The phrase "interwar period" refers to the time between two wars when countries are recovering from the effects of a previous war and preparing for the possibility of another war. Full definition
As the tragedy of the interwar period makes clear, everyone lost. (fortune.com)
Whatever partial rebuilding occurred during the interwar period, however, was more than reversed by wars during much of the 1930s and the first half of the 1940s, so that global capital scarcity continued for at least another decade or two. (carnegieendowment.org)
On the other hand, Spalding notes that Curley, with his «boldness and vigor,» was «without doubt the most open, honest, and outspoken member of the American hierarchy» during the interwar period. (firstthings.com)