Orellana, Francisco de (fränthēsˈkō ħā ōrālyäˈnä) [key], d. c.1546, Spanish explorer of the Amazon River. He took part in the conquest of Peru and was a lieutenant of Gonzalo Pizarro on the expedition that started into the interior of South America in 1538. At the Napo River his detachment was separated from the rest of the expedition, and he floated down the length of the Amazon in one of the most improbable successful voyages in history, arriving at its mouth in Aug., 1541. His tales of female warriors (possibly a mistaken impression of long-haired male warriors) gave the river its name. He died in a subsequent attempt to explore the river from its mouth.