The Indian Ocean is a geographical concept, defined as the world's third-largest oceanic division, covering approximately 70.56 million square kilometers or about 20% of the Earth's water surface. It is bounded by Asia to the north, Africa to the west, and Australia to the east. The name's origin is ancient, with the Latin form Oceanus Orientalis Indicus ("Indian Eastern Ocean") attested as early as 1515, named after India, which projects prominently into it. Earlier names included the Erythraean Sea in Ancient Greek geography and Sindhu Sagar (Indus River) in traditional South Asian geography. The name reflects India's historical centrality to maritime trade routes, with Greek and Roman geographers referring to it as Oceanus Indicus or Indicum Mare.
The ocean's mechanism is characterized by its unique semi-enclosed nature, being landlocked to the north, which makes it the warmest of the major oceans. Its currents are heavily influenced by the seasonal Indian Monsoon System, which causes a unique reversal of currents in the northern part. The deepest point is the Sunda Trench (or Java Trench) at approximately 7,290 meters.
The Indian Ocean connects to the Indian Ocean Rim Association (IORA), an intergovernmental organization established on March 7, 1997, to promote economic cooperation and regional integration among its 23 member states. IORA focuses on six priority areas, including Maritime Safety and Security and Trade and Investment Facilitation. For India, the ocean is central to its SAGAR (Security and Growth for All in the Region) vision.
The boundaries of the Indian Ocean have been subject to change; the International Hydrographic Organization (IHO) in 2002 delimited the Southern Ocean separately, removing waters south of 60°S from the Indian Ocean's extent, while including the northern marginal seas like the Arabian Sea and Bay of Bengal. India's maritime zones, governed by the United Nations Convention on the Law of the Sea (UNCLOS), may also change as the government considers adopting the globally recognized World Geodetic System 1984 (WGS84) datum to define its baselines.