The plural of koala, a gray tree-dwelling marsupial mammal from Australia that eats eucalyptus leaves and looks cuddly but is actually quite grumpy.
From an Australian Aboriginal language (possibly Dharug), the word entered English in the early 1800s when European colonists encountered these animals. The spelling and pronunciation were Anglicized over time.
Koalas aren't actually bears (they're marsupials, not in the bear family at all), but English speakers called them 'koala bears' anyway, so the misnaming is so common that most people think koalas are bears—it's a case where wrong becomes almost right through sheer repetition.
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