Castaneous is an adjective that means chestnut colored.
The Latin word for ‘chestnut’ is castanea (cass TAN ee uh). By the 17th century, this would branch off into several English words, including ‘castanets,’ a small musical instrument made of wood and our word of the day, an adjective to describe something ‘chestnut colored.’ Here’s an example of castaneous in use:
The castaneous tan I acquired last summer took three weeks in Italy and a lot of laying around in the sun. If we had visited Norway, as we first planned to do, my chestnut-colored complexion would have been a lot closer to pale white.