The quirky site, Dear Aunt Nettie has a good post on the word, its origins and its significance.
Oh, that's an easy one. It's the answer to the trivia question:
"What does the word "sockdologize," mean, and why is the word crucial to American history?"
"Sockdologize" and its many variations (sockdologer, sockdollarger, etc.) was a slang term which became very popular in the United States during the 1850s and '60s, and is still used in some parts of the country to this day. It means a forceful or decisive blow a finisher; something that ends or settles a matter and leaves nothing else to follow, a knockdown blow, a decisive overwhelming finish, reply, argument, conclusive remark, or blow, which leaves no possible response.
Random House Unabridged: "His right jab is a real sockdolager." "The revelation of his actual source of income was a sockdolager from which this politician never recovered."
American frontierspersons were famous for their ability to invent new words, like skeedaddle, bushwhack, absquatulate, tarnation, gumption, bulldozer, etc., etc. In British and Continental stage plays of the time a standard comic character was the backwoods American with his outlandish talk and manners. The most famous melodramatist of the time, Dion Boucicault,² made his reputation on wily old American backwoods characters who sounded like ignorant cusses but were able to see through the plots and schemes of the aristocracy and big business.
So what role does this unlikely coinage play in American history?
The adjective form "sockdolagizing" was one of the last words that Abraham Lincoln ever heard.
The play, "Our American Cousin" by Tom Taylor, which was playing at Ford's Theater in Washington DC on the night of April 14, 1865, has a line in in which always brought down the house:
"Well, I guess I know enough to turn you inside out, old gal-- you sockdologizing old man-trap."¹ John Wilkes Booth, an actor himself and aware of the dialog, knew that the line brought the loudest burst of laughter from the audience, and as the audience laughed, Booth fired at that precise moment to muffle the loud noise of his fatal shot.