Pronunciation: ah-REST-oh mo-MEN-tum Description: Used to decrease the velocity of a moving target; it should be noted that it can be used on multiple targets, as well as on the caster himself. Seen/Mentioned: Used by Dumbledore to save one of his students from a fall in 1993 ; Hermione Granger used it, to little effect, in 1998 to cushion an otherwise deadly fall. Etymology: Likely the combination of the Anglo-French arester. meaning "to bring to a stop" and the Latin momentum. meaning "the force or strength gained whilst moving"; the literal translation hence is "Bring the force or strength gained whilst moving to a stop".
Description: Fires arrows from the caster's wand. Seen/Mentioned: The spell used to be used by Appleby Arrows supporters at Quidditch matches to show their support for their teams; however, the British and Irish Quidditch League banned the use of the spell at matches when referee Nugent Potts was pierced through the nose with a stray arrow in 1894.
Ascendio (click for animation)
Pronunciation: ah-SEN-dee-oh Description: Lifts the caster high into the air.
Seen/Mentioned: Used by Harry Potter in the Second Task of the Triwizard Tournament to propel him to the surface of the lake in 1995. Etymology: Derived from Latin ascendo. meaning "to climb". 
Avada Kedavra (Killing Curse)
Cedric employs the Bubble-Head Charm during the Second Task.
Description: Produces a large bubble of air around the head of the user; it is commonly used as the supernatural equivalent of a breathing set. Seen/Mentioned: Used by Cedric Diggory and Fleur Delacour in 1995 ; it was used the next year by many students walking through the halls, because of horrid odours made by various pranks played on Dolores Umbridge.
Calvario (Hair-Loss Curse)
The Hair-Loss Jinx in Lego Harry Potter
Pronunciation: cal-VORE-ee-oh Description: This spell causes the victim's hair to fall out. Seen/Mentioned: In the LEGO Harry Potter: Years 5-7. the book Curses and Counter-Curses by Vindictus Viridian mentions this spell, and it can be bought from Wiseacre's Wizarding Equipment in Diagon Alley. Etymology: From Latin calvus = "bald".
Carpe Retractum (Seize and Pull Charm)