(1) maritime [coastal] province of Rio de Janeiro, now the State of Rio de Janeiro. The city of Rio de Janeiro was so named by Pedro Alvares Cabral who upon entering the Bay of Guanabara in January of 1501, mistaked the bay for a river, hence "river of January". The city of Rio was afterward called Saint Sebastianopolis by the dominican friars who followed Cabral and is referred to as such by von Martius throughout his writings.