Weatherby

Weatherby is the incorrect surname that Professor Horace Slughorn persistently uses when addressing Ron Weasley during Harry Potter and the Half-Blood Prince. This recurring misnomer serves as a running gag that highlights Slughorn's selective memory, which favors students he considers famous, influential, or exceptionally talented, while often forgetting others. The name underscores Ron's feelings of being overshadowed and considered unimportant, particularly in comparison to his best friend, Harry Potter.

The name “Weatherby” is introduced early in Ron's sixth year at Hogwarts.

• First Mention: On the Hogwarts Express, Horace Slughorn invites Harry to join him in his compartment for a preliminary Slug Club meeting. When Ron is present, Slughorn fails to correctly recall his name, referring to him as “Weatherby.”
• Recurring Mistake: Slughorn continues to call Ron “Weatherby” throughout the school year, most notably during Potions lessons. This consistent error reinforces Slughorn's disinterest in Ron, who, unlike Harry or Hermione Granger, does not initially display the kind of exceptional magical talent or famous connections that Slughorn values.
• Correction: Slughorn finally learns and uses Ron's correct surname after a life-threatening incident in his office. After Ron is accidentally poisoned by a bottle of mead intended for Albus Dumbledore, Harry saves his life by forcing a bezoar down his throat. The dramatic event makes a lasting impression on Slughorn, who is deeply shaken. From this point forward, he correctly remembers Ron's name as “Weasley,” signaling that Ron has finally become memorable in his eyes.

“Weatherby” is a genuine English surname of Old Norse and Old English origin. It is a habitational name derived from a place, such as Wetherby in Yorkshire, England. The name is composed of the elements wether, meaning a castrated ram (“wether-sheep”), and -by, a common Old Norse suffix for a “farmstead” or “settlement.” Thus, the name roughly translates to “farm where wether-sheep are kept.” The choice of a somewhat common and unremarkable-sounding English name may have been intended by J.K. Rowling to emphasize how nondescript and ordinary Ron appeared to the status-obsessed Horace Slughorn.

• In the film adaptation of Harry Potter and the Half-Blood Prince, the running gag of Slughorn calling Ron “Weatherby” is largely omitted. In one scene, Slughorn instead mistakenly calls him “Wallenby.” (film)