All these are excellent possibilities but I think the funniest is “the word ‘parsec’ has an actual different meaning in this Galaxy Far Away where everyone speaks something extremely similar to English. (The other very few differences in the language probably include the meaning of 'falcon’)”
I always thought that Millenium Falcon was a spoof of Maltese Falcon.
Like, the Maltese Falcon was something that looked extremely authentic and valuable and had huge amounts of people duped into chasing it, but was actually a shit forgery. (Spoilers? I dunno. That book’s almost 100.)
The Millenium Falcon gets a reaction of “Oh it’s so shit!” from everyone who sees it, so no-one wants it, but it’s actually the best ship in the galaxy, as only people who have actually flown it know.
And perhaps this is the origin of the word “falcon” in-universe
the shitty appearance of the ship, and how it prevents anyone else from wanting it or having any high expectations of it, is Han’s own sort of practical-effect Jedi mind trick… it is a “con” that we “fall” for. hence the name
