War Cabinet

When Churchill was made prime minister of Great Britain, he had to assemble a crew of five to be his new cabinet during wartime. It's like when a new president is inaugurated in the U.S.: they pick a bunch of new secretaries to form their cabinet. Given the urgency of the whole scenario, Churchill put his together very quickly. The same day, actually.

Norway and Holland

When Churchill references these northern European nations, he's referencing the German invasions of Norway in April 1940, and Holland just a month later. These two incidents hit close to home for Great Britain, and led Neville Chamberlain to resign his prime minister gig.

Opposition Liberals

Winston Churchill's political career involved going back-and-forth between the Conservative and Labour (Liberal) Parties (don't those Brits know how to spell?). By the time he became prime minister, he'd been back in the Conservative Party for a long time. However, he and King George VI wanted a coalition government, meaning that all major parties were represented. So the "Opposition Liberals" he mentions refers to the members of Parliament from the Liberal Party that were included in his war cabinet: Clement Attlee and Arthur Greenwood.

Allied Powers

Although some of the alliances in World War II shifted in the first year, ultimately the main Allied forces were Great Britain, the Soviet Union, and, beginning in 1941, the United States. The western European countries were on the Allied side as well, but many were occupied by Germany early on so they couldn't help the war effort. The U.S.S.R. originally had a pact with Germany, but Hitler invaded them in 1941 and they switched sides.

Maginot Line

The Maginot Line was series of fortifications that ran along the eastern coast of France. (You can see a map here.) It was built in the 1930s, and when Hitler started showing interest in expanding Germany's borders (a.k.a. world domination), the Allies thought the line would protect the west from German invasion. They were wrong. The Nazis breezed past the Maginot Line pretty quickly to occupy France.

Axis Powers

The Axis powers were the opposition to the Allied powers. Nazi Germany was the core of the Axis, but the final Big Three included Italy and Japan.

Wehrmacht

The Wehrmacht is the main German national army. This wasn't the infamous SS or Nazi Stormtroopers, but rather the large armies that the Allies would meet on the battlefield. By the time World War II started, the Wehrmacht had become the most effective fighting force in Europe (source).

Reichstag

Nowadays the Reichstag is just one of the landmark buildings of Berlin, but until 1933, it was also the name of the political legislative body of Germany—basically, the German equivalent of Parliament or Congress. After the fall of the Third Reich and the split of East and West Germany, the building fell into disuse and became a museum until it became the home of the Bundestag, the legislative body of the reunified Germany in 1990 (source).

In 1995, the artist Christo wrapped the Reichstag building in a million square feet of silvery fabric and kept it under wraps for two weeks. Because art.

Luftwaffe

Luftwaffe is the German term for an air force, but it was also the official name for the air force of Nazi Germany. It was the main military force that Hitler used to attack Great Britain on their own turf. The Luftwaffe inflicted massive damage on Britain by constant bombing in what's known as the "Blitz," after the German term "blitzkrieg" meaning "lightning war." Should not be confused with Luftwaffles, those buttery, airy German delicacies.