Just about everybody remembers the name “Albus Dumbledore;” Harry Potter’s headmaster in magic school. You’ll find his name in all of the Harry Potter books. But you’ll also find “dumbledore” in the dictionary.
Maybe J. K. Rowling chose the name “Dumbledore” because she thought the word deserved more notice. Back in 1799 John Robberds certainly did: “Is it not the humble-bee, or what we call the ‘dumble dore’,—a word whose descriptive droning deserves a place in song?”
The “dumble” part of “dumbledore” is basically the same word as the “bumble” in “bumblebee.” In this context it means flying erratically rather than in a straight line. The “dore” part is much older — it’s an Old English word for any insect that makes a buzzing noise when it flies. A 1574 book about beekeeping included the word: “If the Dorre bees be over many in the hive..do on this maner.”
Bees are not the only “dumbledores” though; there’s also a “dorfly” that’s sometimes called a “dumbledore,” and there’s a “dor beetle” as well. A dictionary definition of “dumbledore” even mentions the beetle: “the common black dung beetle or dumble-dor ( Geotrupes stercorarius).”
It’s also possible that Rowling was just being ironic when she used the name “Dumbledore” for her smartest character, because “dumbledore” was once a word for someone exactly the opposite; slow or stupid. The word appears in that context in the 1872 novel Under the Greenwood Tree. If you check the sites that explore the etymology of character names in Harry Potter books, though (and there are some), they seem to only mention that “Dumbledore” used to mean “bumblebee.” Maybe Rowling was just trying to create a different kind of buzz.