eldorado:  Eldorado was the name given by the Spanish to a country or city which they believed to exist in the heart of the Amazonian jungle, rich in precious metals and gems. It means ‘the gilded one’: el is the Spanish definite article, and dorado is the past participle of the Spanish verb dorar ‘gild’, a descendant of Latin dēaurāre. This was a compound verb formed from the intensive prefix dē- and aurum ‘gold’. The first known use of the word in English is in the title of Sir Walter Raleigh’s book Discoverie of Guiana, with a relation of the Great and Golden City of Manoa (which the Spaniards call El Dorado) 1596.
1590s, from Spanish El Dorado "the golden one," name given 16c. to the country or city believed to lie in the heart of the Amazon jungle, from past participle of dorar "to gild," from Latin deaurare, from de-, here probably intensive, + aurare "to gild," from aurum (see aureate). The story originated with the early Spanish explorers, and the place was sought for down to the 18th century.