Samudra is referred in the Rig veda as large bodies of water as well as to large Soma vessels. The waters of Samudra are used by Indra and Vishnu in sacred offering while performing oblation. It is believed that Varuna presided over the oceans. There is a literal meaning of the term 'Samudra'. It is said that any mass of water more than one drop could be Samudra, 'water in a jar, a small pool, a large lake, or the sea' can also be called as Samudra.
The Rig veda also says that before the western and eastern Samudra there was an upper and a lower Samudra. The upper Samudra seems to be a heavenly ocean.
The Maruts uplift from the ocean the rain, and fraught with vaporous moisture pour the torrents down and the Soma (moon) and the winds stir the Samudra.
Samudra is said to be the King of Rivers as it does not flow but receive all rivers. It is also mentioned that the Vedic Sarasvati River is the river that flows to the ocean and is pure in her course from the mountains to the sea. There are great rivers that flow to the Samudra but are unable to fill it. Samudra is the eldest of the waters and that the goal of the rivers is the Samudra. The gods referred together with the Samudra are therefore Agni and Soma.
As mentioned in the Puranas the Vedic deity Varuna is the deity of the ocean or Samudra. It is also narrated that Indra slew the dragon which released the seven rivers and caused them to enter the ocean.
Some of the words related with Samudra are salila that means ocean depths and unbounded sea; Arnas, Apas that means water, sometimes Celestial Ocean and Purisha that is the heavenly ocean, clouds. The waves of Samudra are called Urmi and the lakes are called saras, kula, hrada or hlada. Samudra is also known as Sagara.