The harp is a multi-stringed instrument which has the plane of its strings positioned perpendicularly to the soundboard. Organologically, it is in the general category of chordophones (stringed instruments) and has its own sub category (the harps). All harps have a neck, resonator and strings. Some, known as frame harps, also have a pillar; those without the pillar are referred to as open harps. Depending on its size, which varies, a harp may be played while held in the lap or while it stands on a table, or on the floor. Harp strings may be made of nylon, gut, wire or silk. On smaller harps, like the folk harp, the core string material will typically be the same for all strings on a given harp. Larger instruments like the modern concert harp mix string materials to attain their extended ranges. A person who plays the harp is called a harpist or harper. Folk musicians often use the term "harper", whereas classical musicians use "harpist".
Various types of harps are found in Africa, Europe, North and South America and in Asia. In antiquity, harps and the closely related lyres were very prominent in nearly all cultures. The oldest harps found have been uncovered in ruins from ancient Sumer in southern Iraq. The harp also was predominant with medieval bards, troubadors and minnesingers throughout the Spanish Empire. Harps continued to grow in popularity through improvements in their design and construction through the beginning of the 20th century.