Some of [the names] are invented. Voldemort is an invented name. Malfoy is an invented name. Quiddich is invented. But I also collect them from all kinds of places, maps, street names, names of people I meet, old books on saints. Mrs. Norris, people will recognize comes from Jane Austen. Dumbledore is an old English word meaning bumblebee. Since Albus Dumbledore is very fond of music, I always imagined him sort of humming to himself a lot.