The Indus River or Sindhū River,

The Indus River, also called the Sindhū River, or Abāsīn, is a major south-flowing river in South Asia. The total length of the river is 3,180 km (1,980 mi) which makes it one of longest rivers in Asia. It flows through Pakistan, the Indian state of Jammu and Kashmir and western Tibet. Originating in the Tibetan Plateau in the vicinity of Lake Mansarovar, the river runs a course through the Ladakh region of Jammu and Kashmir, towards Gilgit-Baltistan and then flows in a southerly direction along the entire length of Punjab, Pakistan to merge into the Arabian Sea near the port city of Karachi in Sindh. It is the longest river of Pakistan.

The river has a total drainage area exceeding 1,165,000 km2 (450,000 sq mi). Its estimated annual flow stands at around 207 km3 (50 cu mi), making it the twenty-first largest river in the world in terms of annual flow. The Zanskar is its left bank tributary in Ladakh. In the plains, its left bank tributary is the Chenab which itself has four major tributaries, namely, the Jhelum, the Ravi, the Beas and the Sutlej. Its principal right bank tributaries are the Shyok, the Gilgit, the Kabul, the Gomal and the Kurram. Beginning in a mountain spring and fed with glaciers and rivers in the Himalayas, the river supports ecosystems of temperate forests, plains and arid countryside.

The Indus forms the delta of present-day Pakistan mentioned in the Vedic Rigveda as Sapta Sindhu and the Iranian Zend Avesta as Hapta Hindu (both terms meaning "seven rivers"). The river has been a source of wonder since the Classical Period, with King Darius of Persia sending his Greek subject Scylax of Caryanda to explore the river as early as 510 BC.

Etymology and names
The word "Indus" is the romanised form of the ancient Greek word "Indós" (Ἰνδός), borrowed from the old Persian word "Hinduš" which is in turn borrowed from Sanskrit word "Sindhu". Megasthenes's book Indica derives its name from the river's Greek name, "Indós" (Ἰνδός), and describes Nearchus's contemporaneous account of how Alexander the Great crossed the river. The ancient Greeks referred to the Indians (people of present-day India and Pakistan) as "Indói" (Ἰνδοί), literally meaning "the people of the Indus".The country of India and the Pakistani province of Sindh owe their names to the river.
Rigveda and the Indus
Rigveda also describes several mythical rivers, including one named "Sindhu". The Rigvedic "Sindhu" is thought to be the present-day Indus river and is attested 176 times in its text – 95 times in the plural, more often used in the generic meaning. In the Rigveda, notably in the later hymns, the meaning of the word is narrowed to refer to the Indus river in particular, as in the list of rivers mentioned in the hymn of Nadistuti sukta. The Rigvedic hymns apply a feminine gender to all the rivers mentioned therein but "Sindhu" is the only river attributed with a masculine gender. Sindhu is seen as a strong warrior amongst other rivers which are seen as goddesses and compared to cows and mares yielding milk and butter.

Other names
In Urdu, the official language of Pakistan, the Indus is known as دريائے سِندھ (Daryā-e Sindh). In other languages of the region, the river is known as सिन्धु नदी (Sindhu Nadī) in Hindi, سنڌو (Sindhu) in Sindhi, سندھ (Sindh) in Shahmukhi Punjabi, ਸਿੰਧ ਨਦੀ (Sindh Nadī) in Gurmukhī Punjabi, اباسين (Abāsin, lit. "Father of Rivers") in Pashto, رود سند, (Nahar al-Sind) in Arabic, སེང་གེ།་གཙང་པོ (Sênggê Zangbo, lit. "Lion River") in Tibetan, 印度 (Yìndù) in Chinese, and Nilab in Turki.