Kochi (formerly known as Cochin) is the largest (pop. 1,140,605:1991) city in the state of Kerala, India, and is its principal seaport.

The city derives its name from the Malayalam word "Kochazhi" meaning small lagoon. This was shortened to Cochin by the westerners for easy pronunciation. The city reverted back to its original name Kochi in 1996. This change in name was challenged by the city municipal corporation and officially, the city is still called "Cochin".

Also known as "Queen of the Arabian Sea,", Kochi is located in the district of Ernakulam, about 220 km. north of the state capital Thiruvananthapuram.

Old Kochi loosely refers to a group of islands which comprise Willingdon Island , Fort Kochi , Mattancherry etc.

But now Kochi includes Ernakulam city, old parts of Kochi, Kumbalangi and outlying islands. Kochi was famous for its natural harbour and was the centre of the Indian spice trade for many centuries. It is home to a naval base and an airport, and is well connected to all the major Indian cities. Willingdon Island is a large artificial island, created by dredging the Vembanad Lake under Lord Willingdon’s direction. A large shipyard makes ships, especially cruisers and carriers for the Indian Navy and straddles Willingdon Island.

Cochin was once controlled by the United Provinces; it was ceded to the United Kingdom in the Anglo-Dutch Treaty of 1814 in exchange for the island of Banca .

Fort Kochi, situated on the Fort Kochi/Mattancherry peninsula, is the historical part of the city and home to most of the tourist attractions, such as the cantilevered Chinese fishing nets, the Dutch Palace and the Santa Cruz Basilica . Most economic activity is now centred in Ernakulam, however.

The synagogue in Kochi is the oldest in India. Kochi was a major refuge for a large Jewish community, which has all but migrated to Israel now. The Jewish community figured prominently in the business and economic strata of Kochi society. Kochi now has a multicultural and secular community comprising Hindus, Christians, Muslims, Jains, Sikhs and other denominations. Roman Catholicism is a dominant force in the region. Kochi also harboured the grave of Vasco da Gama, the Portuguese explorer, who was buried at St.Francis Church until his remains were returned to Portugal in 1539.

The Cochin University of Science and Technology (CUSAT) is located in Kochi.