What is the X in X-mas?
"Maxim automatic gun," 1899, of imitative origin, soldiers' slang from the Boer War. For the ornamental tuft, see pompom.
"ornamental round tuft" (originally on a hat, etc.), 1748, alteration of pompon "ornamental tuft; tuft-like flower head," from French pompon (1725), of unknown origin; perhaps related to Old French pompe "pomp."
The sex act; screwing
[WWII Army; perhaps fr the echoic name pom-pom of various rapid-fire automatic guns, found by 1889]