Eithan is a spelling variant of Ethan, which comes from the Hebrew Eitan and means "firm", "enduring" or "strong"; in the Old Testament, Ethan the Ezrahite is praised for his wisdom. The spelling with the extra i is especially popular with Hispanic families and mirrors how the name is pronounced in Spanish. Eithan is one of the fastest-rising boys' names in the country: number 1603 in 2015, in the top 1000 since 2019, number 226 in 2024 and number 97 in 2025, its first time in the top 100.