Sri Lanka (; ), officially the Democratic Socialist Republic of Sri Lanka, is an island country in the northern Indian Ocean which has been known under various names over time. Lanka Lak-vaesiyaa in Sinhala means an inhabitant of the island of Lanka. Lak-diva in E'lu (old Sinhala) means 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". The Sanskrit epic Ramayana mentioned it Lanka and the abode of King Ravan. 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 (), 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! Ceylon Under British rule, the island was known as Ceylon from 1815 to 1972. Serendip The name "Serendip" given by Arabs due to Lankan Rubi and pearl. The name Ceylon too originated from an Arabic name "Saheelan" since they had long trading history with Lanka. Then Romans called it "Sielen" The name Ceylon has a complicated history going back to antiquity. Theory states that the name comes from Sielen as the island was known by the Romans as Serendivis and by Arabs as Serandib and the Persians as Serendip (the root from which serendipity is derived) while Greeks called the island Sielen Diva or Sieldiba. The name is said to be based on the word Sinhaladvipa which is also used in the Culavamsa as a name for the Island. From the word Sielen, many European forms were derived: Latin Seelan, Portuguese Ceilão, Spanish Ceilán, French Seilan, Ceylan, Dutch Zeilan, Ceilan and Seylon, and of course the English Ceylon. Ptolemy called the Island Salike, and the inhabitants Salai. Another theory is that the name derives from the Tamil words cheran for the Tamil dynasty of the Chera and the