Interwar period means a period of time between two wars. It usually refers to the time period between World War I and World War II, which was between 1918-1939. During this time, many countries were trying to rebuild their lives after the war and make their countries better places to live. People made new inventions, like cars, airplanes, and radios. Countries worked out treaties and agreements to try and make sure that war wouldn't happen again. It was an important time for the world, because it helped people try to learn from the mistakes of the past and build a better future.