The oud is a pear-shaped, short-necked string instrument that has been a cornerstone of Middle Eastern and North African music for millennia. Its name comes from the Arabic word 'al-oud,' meaning 'the wood.' Unlike the guitar, the oud is fretless, which allows musicians to play the 'microtones' or quarter-tones essential to the Arabic 'Maqam' system. It typically features 11 strings, with 5 pairs tuned in unison and a single low bass string. The oud is played with a plectrum called a 'risha,' traditionally made from an eagle's quill. When the oud was introduced to Europe during the Crusades and the Moorish occupation of Spain, it evolved into the European lute. The most visible difference is that the lute added frets to suit Western scales, while the oud maintained its fretless neck to preserve its ability to slide between notes and express subtle melodic nuances.