The Indian Ocean is the third-largest of the world's five oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi) or approx. 20% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean, or Antarctica, depending on the definition in use. Along its core, the Indian Ocean has large marginal, or regional seas, such as the Andaman Sea, the Arabian Sea, the Bay of Bengal, and the Laccadive Sea.

The ocean is the body of salt water that covers approx. 70.8% of Earth. In English, the term ocean also refers to any of the large bodies of water into which the world ocean is conventionally divided. Distinct names are used to identify five different areas of the ocean: Pacific, Atlantic, Indian, Antarctic/Southern, and Arctic. The ocean contains 97% of Earth's water and is the primary component of Earth's hydrosphere, thus the ocean is essential to life on Earth. The ocean influences climate and weather patterns, the carbon cycle, and the water cycle by acting as a huge heat reservoir.