I've kept this to myself for a year, but now I must speak.
There are seven books of the Old Testament (as well as some bits and pieces in a few other books) that aren't in Protestant Bibles because they were kicked out in the 1500's as the Protestant denominations formed. At the same time Catholics started referring to those parts of the Bible as the "deuterocanonical books". Deuterocanonical means "second canon", which is a bit misleading. The phrase also sounds dorky, has eight syllables and is a pain to say.
Protestants have their own name for the disputed sections: they call them the Apocrypha. That name means "hidden things". It's shorter, it's got punchy consonants and it sounds really, really cool. Pop culture knows this. There's a rock band called Apocrypha, a sort of new age folk Hungarian musical album named Apocrypha, an episode of Law and Order named Apocrypha and an episode of the X-Files named Apocrypha. Do you know any X-Files episodes named The Deuterocanonical Books? Yeah, I didn't think so. I'm sure it's only a matter of time before some celebrity baby gets named Apocrypha Paltrow.
I'm Catholic now and I can't let my side down. But I wish we'd ditch our term and steal the Protestants' instead. It's just so much more fun to say!