Definition of Nigeria from the Oxford Advanced Learner's Dictionary

a large country on the west coast of Africa. It was a British colony from 1914 and has been a member of the Commonwealth since becoming independent in 1960, although between 1995 and 1999 its membership was stopped temporarily after a dispute over the execution of nine men. The capital city of Nigeria is Abuja, in the middle of the country, although its biggest city is Lagos, on the coast. The official language is English. See related entries: Countries and continents
See the Oxford Advanced American Dictionary entry: Nigeria