1. A country of Central America on the Caribbean Sea and the Pacific Ocean. Its Caribbean coastline was discovered by Columbus in 1502, and the first settlements were made by the Spanish in 1524. Nicaragua was ruled as part of Guatemala until it declared its independence from Spain in 1821. Since its designation as a republic in 1838, Nicaragua has had a turbulent history, with frequent intervention by foreign powers. Managua is the capital and the largest city. Population, 2,823,979.