Blitzkrieg is a German word that means "lightning war" and refers to the high speed of a lightning bolt.

In blitzkrieg, the attacking motorized infantry armies move quickly and are helped by tanks and aircraft. Slower-moving enemy units are overrun or surrounded and often captured with little fighting. The slower units often become disorganized and are not ready to fight when they are captured.

The combined arms tactics of blitzkrieg were developed in the 1920s and 1930s, especially in the German Wehrmacht. They seldom used this word, however.

This method worked well early in World War II during the invasions of Poland and France and was mostly successful during Operation Barbarossa. Later in the war, the Allies learned to defeat German blitzkrieg attacks by defence in depth and by attacking the flanks of the attackers with reserve forces.

The Blitz refers to the German bombing of Britain, particularly London, during World War II. It destroyed over a million homes, killed over 40,000 people and was supposed to destroy industry and morale quickly to make the British pressure their government to end the war. The Blitz started in September 1940 in response to the British bombing of German cities by the Royal Air Force and continued until May 1941.