The Rigvedic Aryans were not acquainted with the seas or oceans. M. L. Bhargava in his book The Geography of Rigvedic India has given several allusions to oceans as well as large ships but in all probability words like ‘samudra’, ‘arnva’ or ‘chatuh samudra’ refer to the vast waters of the Indus. But in the later-Vedic literature Samudra actually means the sea.
The references to eastern and western oceans in the Satapatha Brahmana indicate acquaintance with the Bay of Bengal and The Arabian Sea.