To me, the word pee naturally seems like one of those really old terms that didn't change much in spelling or definition over thousands of years of existence. However, its etymology really surprised me: apparently it was first used in 1788 as a euphemistic initialism of the word piss. What started out as a modest letter P then developed a life of its own, to the point where it's more used than its parent and developed offshoots like the noun in 1880 and the 1920s formation pee-pee. The word Piss is more what I envisioned pee to be: through Middle English pissen and Old French pissier, it traces to Vulgar Latin pissiare, which ultimately is probably imitative. To take the piss, which is a British and Australian colloquial phrase meaning "make fun of" and piss-poor both were first coined in 1945, and the first figurative usage of the term pissy is from the 1930s.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.