Xmas. Xmas is neither an abbreviation nor a "vulgar commercial invention" of recent vintage. X has been used to symbolize the syllable "Christ" in English since at least 1100, when it was recorded in Xianity, for "Christianity". The Old English word for Christian recorded in the 12th-century Anglo-Saxon Chronicle begins with an X, and the word Xmas itself was used as early as 1551. The Greek word that gives us the English word Christ begins with the letter chi, or X, leading some writers to believe that the X in Xmas symbolized the cross.
Rub out. To rub someone out, "to kill him," isn't gangster talk from the Prohibition era, as is so often assumed. The term dates back to the early 19th-century American Far West and has its origins in Plains Indian sign language, which expresses to kill with a rubbing motion. The term is first recorded in George Ruxton's Life in the Far West (1848) and it is he who gives the sign language source.
Cooties. Our slang word cooties, for "body lice", derives from the Malayan-Polynesian kutu, "louse", which British sailors became familiar with (both word and nit) in the early years of this century.
To decimate. After any mutiny in the Roman army, or any cowardice, the standard punishment was to take one man by lot out of each of the ten-man squads and have his fellow squad members kill him. From this disciplinary measure came the word decimare (from the Latin decem, ten, meaning "to kill one in ten") that became the English decimate. Decimate strictly means to reduce a military force by one-tenth, but through careless usage has come to mean to destroy a large part of any population, even to obliterate it.
[Back to Keith. So my book title (Xmas Carol) isn't nasty or blasphemous after all. Moo ha ha ha ha!. See? I was just being sweet and historically accurate when I gave the book this title. Oh, and I'm never going to use the word decimate again.]