Niterói (nētəroi´), city (1996 pop. 450,124), Rio de Janeiro prov., SE Brazil, on Guanabara Bay opposite the city of Rio de Janeiro. It is a residential suburb of Rio, and many of its citizens commute to work across the bay. Niterói is also a shipbuilding center. Foodstuffs, transportation equipment, textiles, pharmaceuticals, and metals are the principal products. The area was settled by indigenous peoples in 1573 on land granted by the king of Portugal. The city's name derives from the native word Nyteroi, meaning "hidden water." By 1819, the indigenous community was extinct. In 1835, Niterói became the provincial capital; it was replaced as capital by the city of Rio de Janeiro in 1974 after Guanabara prov. merged with Rio de Janeiro prov.