Eider is used as a boys' name in Colombia and other parts of Latin America, where it is pronounced AY-der; its origin there is uncertain. In the Basque Country Eider is a girls' name from eder, meaning "beautiful", and in English the word names the northern sea duck whose down fills winter jackets. In the United States Eider was almost unknown until the late 2010s and has risen sharply from number 8336 in 2017 to number 1064 in 2025.