Short answers, pulled from the story.
Blitzkrieg is a German word meaning lightning war or lightning attack. The term first appeared in the German military periodical Deutsche Wehr in 1935 and was popularized by British journalism after the fall of France in 1940. Time magazine used the phrase in September 1939 to describe the German invasion of Poland as "a war of quick penetration and obliteration."
No. The Wehrmacht never used blitzkrieg as an official military term except for propaganda purposes and never formally adopted it as a concept or doctrine. Most academic historians, including Karl-Heinz Frieser and Robert M. Citino, regard blitzkrieg as a military doctrine to be a myth. J. P. Harris confirmed that the word did not appear in German army or air force field manuals.
Hitler privately called blitzkrieg "ein ganz blödsinniges Wort" - a completely idiotic word, according to David Reynolds. In a speech in November 1941 Hitler declared, "I have never used the word Blitzkrieg, because it is a very silly word." In early January 1942 he dismissed it as "Italian phraseology."
Guderian was the central theorist of German combined-arms armor doctrine. In 1929 he concluded that tanks required all supporting arms raised to their speed and cross-country performance to achieve decisive results. In 1933 he insisted to the high command that every German tank must carry a radio, a standard only the German Army had met at the start of the Second World War. He also authored the 1937 book Achtung - Panzer!, which Hitler read with strong approval.
Less mechanized than the blitzkrieg legend suggests. In 1939-1940 the German Army had 120,000 vehicles, compared to the French Army's 300,000. Only ten percent of the army was motorized in 1940, and roughly 50 percent of soldiers had only a few weeks of training. The Wehrmacht used 2.7 million horses for transport in the Second World War. Karl-Heinz Frieser described the image of a fully mechanized German blitzkrieg army as "a figment of propaganda imagination."
At Kursk in July 1943 the Stavka, forewarned of German intentions through front-line reconnaissance and Ultra intercepts, constructed deep defensive belts along the planned German axis of attack. Rather than contesting the breakthrough at the forward edge, Soviet forces absorbed German combat power across successive defensive belts before transitioning to the offensive. David Glantz stated in 1995 that blitzkrieg was defeated in summer conditions for the first time at Kursk.