What is the origin of euxinia?
Euxinia “anoxia in a body of water” is the namesake of the Latin term Pontus Euxīnus “the Black Sea,” where euxinia is often found in the deeper water. The Latin name is adapted from Ancient Greek Pontos Euxeînos, literally “hospitable sea,” but the story does not end there. It appears that the euxeînos portion, meaning “hospitable” and composed of eu- “good” and xeînos “foreign” (a variant of xénos; compare English xeno-), was originally a euphemism for Pontos Axeînos “inhospitable sea.” Alternatively, the meaning of the axeînos element could be folk etymology, that is, incorrectly derived from an unrelated term; the name for the Black Sea in Avestan, an ancient Indo-European language of the Iranian plateau, contained the element axšaēna- “blue, dark,” and speakers of Ancient Greek could have misinterpreted this word as their own axeînos. Euxinia was first recorded in English in the early 1950s.