Well, I guess today's as good a day as any to wrap up my whole "How did the months get their names?" series I've been doing all year, even though since September the answer has pretty much been these used to be the seventh, eighth, ninth, and tenth months of the year until they got booted back two spots by the addition of two months in the Julian calendar.  Somehow they still retained their original names, which had prefixes related to their numerical spot.  We're pretty used to dec- being a prefix meaning 10 such as the decimal system and whatnot, thus without even looking anything up I can say with nearly complete confidence that this is how December got its name.  It used to be the tenth month, the name reflected that, and it was never changed after it became the twelfth month.  Just in case there's anything I'm missing here, I'll go look up the info right now, but I'm betting there's not much more to it than that.  Be right back...

Yeah, the only thing I can add after looking it up was the Latin word for ten is literally "decem."  So yeah, it's ten month and that's all there is to it really.  Eh, the earlier months of the year were a lot more interesting when it came to this particular exercise, but I figured I may as well see it through to the bitter end.