Entymology: Apparently, way back in the days of the 1960s, a game show known as "Password" had a celebrity giving word association clues to a contestant in order for them to say a certain word. After winning the main game, the contestants moved on to the "Speed Round" in which contestants were give 30 seconds to guess 4 difficult words, each being worth $50 in value. The fourth word was usually long or difficult. Since if you got all of them right you got $200, that last one before winning became the "$200 word".
Jack: Stop using those $200 words! You could of easily said you were eating dinner and your girlfriend was lying about something!