Muggles' Guide to Harry Potter/Magic/Banishing Charm

Overview
Banishing Charms are the opposite of Summoning Charms, and are used to send an object away from the caster.

Extended Description
Banishing charms are more difficult than summoning charms as you are not only impelling an object to move, but ideally you are also telling it where to move to. In Professor Flitwick's class, we see that while nearly everyone has managed to send objects away from themselves (though in the case of Neville's efforts, sometimes it is the wrong object), only the best of the students is able to send their pillows unerringly into the box where they are intended to go.

We never hear the actual invocation of the banishing charm.