What does the 'K' in J. K. Rowling stand for?

The “K” in J. K. Rowling stands for Kathleen. Rowling was born Joanne Rowling and did not originally have a middle name. Her publisher, Bloomsbury, suggested using two initials because it feared that some young male readers might avoid a book written by a woman. Rowling chose “K” in honour of her paternal grandmother, Kathleen Rowling, creating the pen name J. K. Rowling.

The initial was therefore not short for Joanne, and Kathleen was not originally part of Rowling’s legal birth name. After her first marriage, she sometimes used Joanne Murray in private affairs, but she continued publishing as J. K. Rowling. She is also widely known simply as Jo, a nickname she has said was used by family and friends.

The Harry Potter novels appeared under this name from Harry Potter and the Philosopher’s Stone in 1997 through Harry Potter and the Deathly Hallows in 2007. A related mix-up is the “J”: it represents Joanne, not Jessica or Jane.