Original: The Vespucci expedition also named the Potengi (Tupi-Guarani for "River of Shrimps") river, whose considerably large mouth contrasted with the nearby bodies of water, "Rio Grande" (Portuguese for "Great River"), after which the Captaincy, Province, and State were named.
Simplified: The Vespucci expedition also named the Potengi river, "Rio Grande". The name is Portuguese for "Great River". It is often called the "Brazilian NASA".