Before 1300 as onix, in about 1250 as oneche, from Old French oniche or onix, from Latin onyx, from Ancient Greek ὄνυξ (onyx).
onyx (countable and uncountable, plural onyxes)
- (mineralogy) A banded variety of chalcedony, a cryptocrystalline form of quartz.
- A jet-black color, named after the gemstone.
- (entomology) Any of various lycaenid butterflies of the genus Horaga.
onyx (not comparable)