Type: Charm
Pronunciation: ah-LOH-ho-MOR-ah
Description: Unlocks doors and other objects. It can also unlock doors that have been sealed with a Locking Spell, although it is possible to bewitch doors to become unaffected by this spell.
Seen/Mentioned: Used by Hermione Granger in 1991 to allow her and her friends to access the Third-floor corridor] at her school, which was at the time forbidden; she used it again two years later to free Sirius's cell in her teacher's prison room.
Etymology: The incantation is derived from the West African Sidiki dialect used in geomancy; it means "friendly to thieves", as stated by the author in testimony during a court case.
Notes: Whilst in the first book, when the spell is cast the lock or door must be tapped once, in the fifth, a healer simply points her wand at the door to cast it, and on Pottermore the wand motion is seen as a backward 'S'.