The titular slang for Chicago is infinitely more whimsical than it lets on. The word Chicago is from the Native American language Potawatomi, where the phrase shikaakwa, or "place of the smelly onion", became eponymous with the place that is now the third-largest American city. This is not uncommon; Native Americans often attributed food names to locations. It is also not uncommon for foodstuffs to have been named after animals, so it is unsurprising that shikaakwa comes from the Proto-Algonquin word sekakwa, which meant "skunk". The "smelly" semantic connection is evident. This is reconstructed as coming from the earlier Proto-Algonquin root sek, which meant "to urinate" and further displays the continued prevalence of smell in the definitions (additionally, it may have combined that with the word for "fox", but this is on shaky ground). From that very same prior word (sekakwa) we get our current word for skunk; it passed through the Abenaki language as segonku and was colloquially known as squunk in the area until the current spelling was coined in the mid-seventeenth century. A brief point of interest: a Chicago study by Nina Fascione, et al., found that there were over 4000 skunks "handled by wildlife control operators in the Chicago metropolitan area". Oh, the irony!
Adam Aleksic has been described as the internet's sixth most famous etymologist. He loves writing about himself in the third person, he's a freshman at Harvard University, and he has disturbing interests in linguistics, vexillology, geography, board games, limericks, and law.
The Etymology Nerd