Daisy Hookum (b. 1962) was a witch, who wrote a best-selling book, My Life as a Muggle, after voluntarily giving up using magic for a year. She was married to celebrity Herbologist, Potioneer and radio presenter Tilden Toots.
Simply from the English word for the white flower, ultimately derived from Old English dægeseage, meaning "day eye". It was first used as a given name in the 19th century, at the same time many other plant and flower names were coined.