Bagpipes are a woodwind instrument using enclosed reeds fed from a constant reservoir of air in the form of a bag. The Scottish Great Highland bagpipes are the best known examples in the Anglophone world, but people have played bagpipes for centuries throughout large parts of Europe, Anatolia, the Caucasus, Northern Africa, Western Asia, and around the Persian Gulf. The term bagpipe is equally correct in the singular or the plural, though pipers usually refer to the bagpipes as "the pipes", "a set of pipes" or "a stand of pipes".