Eiden is a recent spelling of Aiden, the anglicized form of the Irish Aodhán, which means "little fire" after Aodh, the Celtic god of the sun and fire. The spelling with Ei- is especially common among Spanish-speaking families, where it matches the pronunciation. In the United States Eiden stood at number 2365 in 2015, entered the top 1000 in 2023 and has shot up to number 537 among boys' names in 2025, its best rank so far.