köken: Perhaps from Latin aerūginem (“rust”), from aes, aeris (“bronze”) + -ūgō (forms nouns denoting superficial coatings). Or possibly from Late Latin arānea (originally spider's web, later coming to refer to skin diseases such as herpes, scabies, impetigo, etc.) crossed with rodere (“to gnaw”) into a Vulgar Latin form *aronea or *ronea. Compare French rogne, Catalan ronya, Spanish roña, Portuguese…