'ud
The oud ((/uːd/)) is a short-neck lute-type, pear-shaped stringed instrument (a chordophone in the Hornbostel-Sachs classification of instruments) with today 11 or 13 strings grouped in 5 or 6 courses, commonly used in Arabian, Greek, Turkish, Jewish, Byzantine, Azerbaijani, Armenian, North African (Chaabi, Classical, and Spanish Andalusian), Somali and Middle Eastern music.
In the first centuries of Arabian civilisation, the oud had 4 courses (one string per course - double-strings came later) only, tuned in successive fourths. These were called (for the lowest in pitch) the Bamm, then came (higher to highest in pitch) the Mathnā, the Mathlath and the Zīr. A fifth string (highest in pitch, lowest in its positioning in relation to other strings), called ḥād ("sharp"), was sometimes added for theoretical purposes, generally to complement the double octave.
The Modern tuning preserves the ancient succession of fourths, with adjunctions (lowest or highest courses) which may be tuned differently following regional or personal preferences.
The first mention of an actual fifth string is by 11th-century musician, singer and author Abū-l-Ḥasan Muḥammad ibn al-Ḥasan ibn a-ṭ-Ṭaḥḥān in his compendium on music Ḥāwī al-Funūn wa Salwat al-Maḥzūn.
The first known complete description of the ‛ūd and its construction is found in the epistle Risāla fī-l-Luḥūn wa-n-Nagham by 9th-century Philosopher of the Arabs YaꜤqūb ibn Isḥāq al-Kindī. Kindī's description stands thus:
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