Indian Ocean

American  

[in-dee-uhn oh-shuhn] / ˈɪn di ən ˈoʊ ʃən /

noun

1. an ocean south of Asia, east of Africa, and west of Australia, with its deepest section in the Java Trench. 27,243,268 square miles (70,560,000 square kilometers).

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Indian Ocean British  

noun

1. an ocean bordered by Africa in the west, Asia in the north, and Australia in the east and merging with the Antarctic Ocean in the south. Average depth: 3900 m (13 000 ft). Greatest depth (off the Sunda Islands): 7450 m (24 442 ft). In December 2004 a major undersea earthquake off Sumatra triggered a tsunami which affected large areas of the ocean as far away as east Africa, and killed an estimated 226 435 people. Area: about 73 556 000 sq km (28 400 000 sq miles)

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Indian Ocean Cultural  

1. Third-largest ocean (after the Atlantic Ocean and Pacific Ocean), extending from southern Asia to Antarctica and from eastern Africa to southeastern Australia.

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Etymology

Origin of Indian Ocean

First recorded in 1580–90

Example Sentences

Last September, the Indian Ocean island was rocked by weeks of youth-led protests, which helped topple the country's then President Andry Rajoelina.

From BBC • Apr. 29, 2026

In 1965, during the heat of the Cold War, the U.K. declared the Chagos the British Indian Ocean Territory.

From The Wall Street Journal • Apr. 28, 2026

Until three years ago piracy had almost disappeared in this stretch of the Indian Ocean once notorious for hijackings, but it has since made a comeback.

From BBC • Apr. 27, 2026

At that stage, magma will rise through the fractures to form new seafloor, and water from the Indian Ocean to the north could eventually flood in.

From Science Daily • Apr. 25, 2026

Astonishingly, it also swept westward across the Indian Ocean to the east coast of Africa, resulting in the colonization of the island of Madagascar.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond