Where did that name come from?
I met a British journalist from quite a serious newspaper not very long ago. She said to me: "You obviously got the name 'Quidditch' from 'quiddity,' which is the word that means the essence of a thing." And I looked at her and thought, "Oh, I really want to say, 'Yes.' Because that sounds so much cooler than the truth." But the truth is that I invented the word for a totally whimsical reason. I just wanted a word that began with Q. Don't ask me why. Just pure whim. I still have the notebook in which I invented all these words beginning with Q. On the page, you can see where I wrote Quidditch, and I circled it five times. I just really liked the sound of it.
(из интервью с Роулинг)