Eilish is the Irish form of Elizabeth, meaning 'God is my oath.'
Eilish is the Irish language form of Elizabeth, one of the most consequential names in Western history. The journey begins in Hebrew with 'Elisheba,' composed of 'El' (God) and 'sheva' (oath or abundance), meaning roughly 'my God is an oath' or 'pledged to God.' The name belonged to the wife of Aaron in the Book of Exodus, and in its Greek form Elisavet it passed to Elizabeth of the New Testament — the mother of John the Baptist — before spreading across Europe through Christianity's expansion.
By the medieval period, Elizabeth had taken root in virtually every European language, spawning dozens of vernacular variants. In Irish, the name became Eilish (pronounced 'AY-lish'), preserving the ancient Hebrew essence while acquiring the soft, breathed quality that characterizes so many Gaelic names. It remained largely confined to Ireland and the Irish diaspora for much of its history, worn quietly alongside better-known anglicizations like Eliza, Lisa, and Elspeth.
Irish Revival movements of the 19th and 20th centuries encouraged parents to choose native-language forms of classical names, which helped Eilish maintain a steady presence. In the 2010s, Eilish underwent a dramatic global renaissance with the rise of Billie Eilish, the Los Angeles-born singer-songwriter who became one of the most celebrated musicians of her generation. Her surname (originally a middle name) introduced the form to audiences worldwide, triggering a sharp rise in usage across English-speaking countries. The name now carries the cool, understated edge of Irish heritage fused with thoroughly contemporary resonance — old roots, new wings.