[1] Originally pronounced as l̥induk[2] or *qʰl'iːn tuɡ 天竺 in Old Chinese, it comes from the Chinese transliteration of unattested Old Persian diminutive *Hinduka-, which is from attested 𐏃𐎡𐎯𐎢𐏁 h-i-du-u-š (Hindu),[3] which is itself derived from the Proto-Indo-Iranian *síndʰuš, the etymon also of Sanskrit Sindhu, the native name of the Indus River.
Persians travelling in northwest India (present-day Pakistani Sindh and Punjab) named the subcontinent after the river around the 6th century BC.
Yuāndú[5] (身毒 OC n̥i[ŋ][d]ˤuk) appears in Sima Qian's Records of the Grand Historian and Tiandu (天篤) is used in the Book of the Later Han.
A detailed account of Tianzhu is given in the "Xiyu Zhuan" (Record of the Western Regions) in the Hou Hanshu compiled by Fan Ye (398–445): "The state of Tianzhu: Also, named Yuandu, it lies several thousand li southeast of Yuezhi.
The land produces elephants, rhinoceros, tortoise shell, gold, silver, copper, iron, lead, and tin.