The Locking Spell

• Incantation: Colloportus
• Pronunciation: kol-oh-POR-tus
• Wand Movement: Unknown
• Light: None described in the books
• Effect: Magically locks and seals a door. The spell often creates an audible “squelching” or “clicking” sound, indicating the door has been secured. It prevents the door from being opened by non-magical means.
• Type: Charm

The Locking Spell is a practical Charm used to secure doors. While the incantation Colloportus is not formally introduced until the fifth book, an unnamed locking spell with an identical effect is used earlier in the series.

• In Harry Potter and the Philosopher's Stone, Hermione Granger uses a locking spell taught to her by Professor Flitwick to lock a door in the third-floor corridor, temporarily trapping the three-headed dog, Fluffy, behind it.
• In Harry Potter and the Order of the Phoenix, the spell is used extensively. Hermione Granger teaches the incantation Colloportus to Harry Potter while they are at Number Twelve, Grimmauld Place. Later, during the battle in the Department of Mysteries, Hermione and other members of Dumbledore's Army cast it repeatedly on doors to slow down the pursuing Death Eaters. This event also demonstrated the spell's limitations, as the Death Eaters were able to blast the magically locked doors open with more powerful magic.
• In Harry Potter and the Half-Blood Prince, Harry Potter uses Colloportus to lock Professor Horace Slughorn in his office in an attempt to retrieve a crucial memory. Slughorn, a highly skilled wizard, effortlessly undoes the spell with a nonverbal flick of his wand.
• In Harry Potter and the Deathly Hallows, Hermione Granger once again uses the spell to seal the door of a cafe on Tottenham Court Road after she, Harry, and Ron Weasley are ambushed by the Death Eaters Antonin Dolohov and Thorfinn Rowle.

The Locking Spell appears to be a standard Charm taught in the Hogwarts curriculum. Given that Hermione Granger could perform it in her first year, it is likely not an overly difficult spell to master. The primary counter-spell is the Unlocking Charm, `Alohomora`, which is designed specifically to open locked doors and containers. However, the Locking Spell can also be overcome by more powerful magic. As demonstrated by the Death Eaters in the Ministry of Magic and by Professor Slughorn, a simple locked door provides little resistance to a powerful or skilled wizard, who can either counter the Charm directly or simply destroy the door itself.

The incantation, Colloportus, is derived from Latin.

• Collo-: This is likely an assimilated form of the Latin prefix con-, meaning “together” or “with.”
• Portus: This is the Latin word for “door” or “gate.”

When combined, Colloportus can be literally translated as “to bind the door together,” an accurate description of the spell's function of sealing a doorway.

• In the film adaptation of Harry Potter and the Order of the Phoenix, when the spell is used in the Department of Mysteries, it is accompanied by a mechanical clicking sound, and a shimmering, magical lock often materializes on the door before vanishing. (film)
• The Locking Spell appears in numerous Harry Potter video games, typically as a utility spell for the player to lock doors, often to impede enemies or solve puzzles. (video game)