a country in the SW Pacific consisting of a group of nine main islands, formerly called the Ellice Islands; pop. 12,400 (est. 2009); official languages, English and Tuvaluan (local Austronesian language); capital, Funafuti. The islands formed part of the British colony of the Gilbert and Ellice Islands but separated from the Gilberts after a referendum in 1975. Tuvalu became independent within the Commonwealth in 1978.