Sri Lanka (Sinhalese: ශ්රී ලංකා, Śrī Lankā; Tamil: இலங்கை, Ilaṅkai), officially the Democratic Socialist Republic of Sri Lanka, is an island in the Indian Ocean which has been known under various names over time. Under British rule, the island was known as Ceylon from 1815-1948.
Lanka was the classical name bestowed on the island by the Ramayana, an ancient Indian Sanskrit epic poem, where the divine prince Rama rescues his wife beautiful Sita from the demon king Ravana in Lanka.
Lak-diva in E'lu (old Sinhala) means the island of Lanka. Lak-vaesiyaa in Sinhala (the native language of the Sinhalese people, who make up the largest ethnic group in Sri Lanka) means an inhabitant of the island of Lanka. Another traditional Sinhala name for Sri Lanka was Lakdiva, with diva also meaning "island". A further traditional name is Lakbima.Lak in both cases is derived again from Lanka. The same name could have been adopted in Tamil as Ilankai; the Tamil language commonly adds "i" before initial "l".,
Another possible theory is that the name Lanka is derived from the Tamil word "ilanku" (இலங்கு), which means "to shine" or "to glitter", thus making Lanka a name that means "that which glitters". It earned this name on account of the glittering of the gold and gems found on its surface.
At the time of Gautama Buddha in India, the founder of the Buddhism (the largest religion in Sri Lanka) 2,500 years ago Sri Lanka was known as Lankadweepa (dweepa means island). He is said to have visited the island .
The name of Sri Lanka was introduced in the context of the Sri Lankan independence movement, pushing for the independence of British Ceylon during the first half of the 20th century. The name was used by the Marxist Lanka Sama Samaja Party, which was founded in 1935. The Sanskrit honorific Sri was introduced in the name of the Sri Lanka Freedom Party (Sinhalese: ශ්රී ලංකා නිදහස් පක්ෂය Sri Lanka Nidahas Pakshaya), founded in 1952. The Republic of Sri Lanka was officially adopted as the country's name with the new constitution of 1972, and changed to "Democratic Socialist Republic of Sri Lanka" in the constitution of 1978.