The color sepia has a rotten origin. The term, which either describes a color or a kind of muted brown filter used in photography and social media, actually comes from the Latin word sepia, originally. This, surprisingly enough, meant "cuttlefish", the connection being that the cephalopod (a relative of the squid) releases a dark brown ink used by the classical Mediterranean civilizations. Not much changes as we trace it back further to the Greek word sepia, with the same meaning, but here it gets interesting. Possibly through the name for another disgusting aquatic animals, seps, this appears to have roots in sepein, meaning "to become rotten", because the seps animal's bite could cause infection. Here the origins get really obscure, but it might have connections to other words to do with rottenness, like Ancient Greek for "sore" and "decay". Despite all the online use, the word sepia has decreased in usage over the past few decades.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd