Which Harry Potter book is the only main-series novel whose title includes the word “Deathly”?

Harry Potter and the Deathly Hallows is the only main-series Harry Potter novel whose title includes the word “Deathly.”

It is the seventh and final novel in J.K. Rowling’s main Harry Potter series. Bloomsbury published it in the United Kingdom on 21 July 2007, ending the central story of Harry, Ron Weasley, and Hermione Granger. The plot follows their search for Voldemort’s Horcruxes while the wizarding world is controlled by Voldemort’s forces.

The title refers to three legendary magical objects: the Elder Wand, the Resurrection Stone, and the Cloak of Invisibility. Together they are called the Deathly Hallows. The book’s title is therefore both a clue to the mythology and a reference to the final quest.

The film adaptation was divided into two parts, released in 2010 and 2011. That division applies to the movies, not to the original novel, which is one complete book.