But to interject some complications into the picture, Perl stands for both of those more than, say, Perl's an Extremely Reliable Language. Why do I say that? Because Larry Wall has said that he thought up the previous two backronyms while trying to come up with a name for his new language, and liked the wordplay. To the best of my knowledge he hadn't thought up the one that I just listed. (Though knowing him he might have though up those and a dozen more, but just liked the other two better.) So the existence of fun backronyms is part of why the name Perl was chosen, but Perl itself doesn't actually stand for anything and was never meant to.

Update: Oops, Womeone Who Would Know privately corrected me on the backronym and verified the rest of what I said.