In Persian, the word means "string". It has been mentioned in classical Persian literature by Rudaki, Hafez, Naser Khusraw, Sanai, Ferdowsi, Nizami and Qatran Tabrizi other poets. The Arabic 'Ud, whose etymology is not yet convincingly explained, may well have been derived from the Persian word rud.
Text adapted from Wikipedia, CC BY-SA 4.0. Photograph: David Kernan (see Commons), Wikimedia Commons.