"The wand chooses the wizard... it's not always clear why."

-Ollivander-

A wand is a quasi-sentient magical instrument through which a witch or wizard channels her or his magical powers to centralise the effects for more complex results. Most spells are done with the aid of wands, but spells can be cast without the use of wands. Wandless magic is, however, very difficult and requires much concentration and incredible skill; only truly advanced wizards are known to perform such magic. 

 Magic with a wand is usually performed with an incantation, but more experienced wizards can cast nonverbal spells, which conceal the spell until cast and may thereby prevent an opponent from adequately protecting him- or herself in time. Wands are referred to as "quasi-sentient" because their being imbued with a great deal of magic makes them as animate as an inanimate object can be.

 Wands are manufactured and sold by wandmakers, the most famous of these in Great Britain being Ollivander and Gregorovitch. Each wand consists of a specific type of wood that surrounds a core of magical substance. Although the wand cores may come from the same creature, or the wood may come from the same tree, no two existing wands are exactly alike. The study of the history and the magical properties of wands is called wandlore.