Likely a modern literary-style name related to Helen or Welsh Elin forms, suggesting brightness.
Aelin exists at the meeting point of ancient Celtic phonetics and contemporary fantasy literature. The name's sound and structure echo Welsh and broader Brittonic naming traditions, where names like Elin (a Welsh form of Helen, from the Greek "helene" meaning torch or bright light) have been common for centuries. Helen herself is one of the ancient world's most storied names — carried by the mythological figure whose abduction precipitated the Trojan War, and by Saint Helena, mother of Emperor Constantine the Great, who legendarily discovered the True Cross in Jerusalem in the fourth century CE.
In the twenty-first century, Aelin gained its most prominent cultural footprint through Sarah J. Maas's Throne of Glass fantasy series, which began publication in 2012. The protagonist, Aelin Ashryver Galathynius, is a complex and powerful figure — assassin, queen, and wielder of fire magic — whose arc across eight novels made her one of the most discussed characters in the young adult fantasy genre of the 2010s.
Maas's series attracted tens of millions of readers globally, and character names from beloved fantasy series have historically influenced baby naming in measurable ways. Aelin thus occupies a fascinating dual existence: a name rooted in the ancient Celtic tradition of brightness and illumination, now blazing with the associations of a ferocious fictional heroine who reclaimed her identity and her kingdom.