Nick was turned on by my use of the word internecine in this post. I decided to look up its origins, never having studied Latin, and it turns out that our modern use of the word is due to an error in interpretation made by Samuel Johnson in his famous dictionary:

The prefix inter– was here used not in the usual sense “between, mutual” but rather as an intensifier meaning “all the way, to the death.” This piece of knowledge was unknown to Samuel Johnson, however, when he was working on his great dictionary in the 18th century. He included internecine in his dictionary but misunderstood the prefix and defined the word as “endeavoring mutual destruction.” Johnson was not taken to task for this error. On the contrary, his dictionary was so popular and considered so authoritative that this error became widely adopted as correct usage. The error was further compounded when internecine acquired the sense “relating to internal struggle.”

This reminds me of one of those Passover Haggadah passages about rabbinical analysis that someone at the table reads aloud while everyone else is getting impatient for dinner.