Which came first, the definition of poop or the definition of a poop deck?

It’s not as obvious as it looks; officers in the aft quarters would use chamber pots, while the enlisted had to hang their asses over the side of the bow near the bowsprit and hope this was not their last crap. That’s why they call it the “head.”
Also, when I was growing up. ‘poop’ meant fart. It wasn’t until I saw a Japanese children’s book called “Everybody Poops” that I realized it could mean shit.