Flamingo was borrowed into English from the Portuguese word flamengo when the Portuguese started exploring the New World and discovering flocks of this exotic fauna in the Caribbean and South America. Flamengo came from the Latin word flamma (flame), because of the bird's bright pink and red colouring (flamingo trivia: this is due to carotene in its diet, sometimes supplemented in zoos by food colouring!).
Interestingly, though, in Spanish, the word flamenco is used for both the pink birds and the stirring music and dance style originated by gypsies. Although the origin of flamenco is uncertain, it is also the word for "Flemish" in Spanish, and it is thought may have been used indiscriminately by Spaniards for anyone they deemed "foreign".
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