This factoid is by way of the Volokh Conspiracy.

Oil derricks, it turns out, are named (indirectly) after someone named Derrick—not an oil man, though, but a hangman: According to the Oxford English Dictionary, the word (which originally referred to hangmen and gallows) comes from Derrick, the surname of a noted hangman at Tyburn c 1600. 

In Elizabethan times there was no “drop.” The prisoner had the support pulled out from underfoot. They then dangled until they suffocated.

If the condemned could afford to tip the hangman, then hangman would give the dangling body a good yank and break the condemned person’s neck.

Oh, for the good old days!