German. Its historical significance was blowing shit up during WWII.
Iz German for ze “lightning war”. Ze combinzed arms of Panzers (tanks), Luftwaffe (air), Panzergrenadier (mechanized infantry) and Farfegnugen.
Discussed in this recent post.
That’s awesome. 
However, what I was actually saying is that a medium-to-easy factual question is our shibboleth; we’ll cheerfully line up to answer it and prove we’re real [del]Israelites[/del] Dopers.
That.
How and why did Ellen Cherry edit the OP’s OP?
Because his original title said “any reference sort,” rather than “source,” which is what he pretty clearly intended. I assume he self-reported the post and asked her to change it for him.
Blitz in German, meaning “lightning”: by my understanding, Blitzkrieg = initially (as referenced in the thread), conquest by overrunning territory with rapid / concentrated / devastating force. The British seem to have borrowed the word to use it to refer particularly to heavy aerial bombing onslaughts: in Brit-speak, “the Blitz” refers first and foremost to the German air force’s to-the-max bombing offensive on Britain – above all, on London – in 1940 / 41, and sporadically recommenced at later times in the war. General implication of the word in British English would seem to be, “nasty intensive war-waging kind of stuff, especially if done from the air”.
Literally ‘Lightening Wall’; German interior designers in the 1940s felt their houses were far too dingy.
How did I do?
Blitzkreig is German. Means lightning war. It refers to Germany’s used of tanks and mechanized infantry divisions to attack and overwhelm opponents before they can prepare a defense.
It means something like “fast, lightning quick strike”
Its German
In WW2, the German airforce Luftwaffe self-described their many raids on London as a blitzkrieg
Did I get it right? 
…
Alright, mostly right!
German, WWII, “lightning war”, to counterpoint Sitzkrieg, the “sitdown war”.
It’s a Swahili term meaning, “the fog sits lightly o’er the forest”, used metaphorically to describe a situation in which each member of a group thinks somebody else was responsible for bringing doughnuts.
I can’t believe noone else mentioned sitzkrieg. 
It’s from the Bible (the Old Testament). One tribe was sending people to spy on another tribe. But the first tribe had a different accent and pronounced “sh” as “s”. So the second tribe had strangers say shibboleth. If they said sibboleth, they were killed. It became a metaphor for a characteristic which defines the difference between the members of two groups.
Blitzkrieg is German for Lightning War.
This was the strategy the Germans used in WWII that involved beginning a war by throwing everything they had into the first, sustained attack. Infantry, tanks & aerial bombardment…
Very nice, but I was actually answering my own question; I was saying that asking a (relatively) softball factual question here is our shibboleth, as Dopers cheerfully line up to prove how smart we are.
I’d call Sherman’s march more of a Scorched Earth Advance…
It’s a powerful light that has been jury-rigged to cook crepe-like pancakes.
Did I get it right?
“Lightning war”
German armor strategy/doctrine in WWII.