| Term | Definition |
| Professor Trelawney | Made the prophecy concerning Harry and Voldemort |
| Severus Snape | The Half-Blood Prince |
| Aragog | Hagrid's enormous spider |
| Professor Slughorn | Told Tom Riddle about Horcruxes |
| Fawkes | Dumbledore's phoenix |
| Dumbledore's Army | Hogwarts students led by Harry to learn defensive spells |
| Remus Lupin | A werewolf and friend to James |
| Ginny Weasley | Harry's girlfriend |
| Tom Marvolo Riddle | Voldemort's real name |
| R.A.B. | Person who stole the locket and left a fake in its place in the cave |
| Narcissa Malfoy | Person with whom Snape makes an Unbreakable Vow |
| Felix Felicis | A potion bringing tremendous luck |
| Sirius Black | Harry's godfather and the prisoner of Azkaban |
| Kreacher | The Black family house elf |
| Draco Malfoy | Failed his attempts to kill Dumbledore |
| Mirror of Erised | Show your heart's greatest desire |
| Dolores Umbridge | DADA professor in year five |
| Cedric Diggory | Died at the end of the Triwizard Tournament |
| Barty Crouch, Jr. | Impersonated Professor Moody during year four |
| Hermoine Granger | Person Ron Weasley really likes |
| Godric's Hollow | Place Harry's parents are killed |
| Ollivander | Sells wands in Diagon Alley (until captured) |
| Madam Malkin | Sells robes in Diagon Alley |
| Weasley twins | Sells Skiving Snackboxes and other funny items in Diagon Alley |
| Hog's Head | Dark and shady Pub in Hogsmeade |
| The Leaky Cauldron | Pub with the entrance to Diagon Alley |
| The Three Broomsticks | Popular pub in Hogsmeade |
| Borgin and Burke | Sells dark magic items in Knockturn Alley |
| Diary | Horcrux destroyed in year two |
| Ring | Horcrux destroyed in year six |