Where does “koŝmaro” come from?
koŝmaro (Esperanto) comes from Russian кошма́р, from French cauchemar, from Middle French cauchemare, from Old French cauquemare, from Norman cauche, from Old French chauce, from Vulgar Latin calcea, from Latin calceus — small stone, pebble; gravel, rubble.
koŝmaro (Esperanto): nightmare
Ancestry of “koŝmaro”, step by step