Variant of Arlen, possibly from Irish Gaelic meaning pledge or oath.
Arlin draws from Celtic and Gaelic naming traditions, functioning as a variant of Arlen or Arlin — names rooted in the Irish word for "pledge" or "oath" (ár), with some scholars also connecting it to the Gaelic airling, meaning "vision" or "dream." This latter meaning gives the name an unexpectedly lyrical quality: to be named Arlin, in one reading, is to be named for the act of visionary dreaming itself. The name also circulates as a variant of Arline, the feminine form popularized in the nineteenth century, and as a surname-turned-given-name in the Anglo-Irish tradition of repurposing family names.
Arlen Specter, the longtime Pennsylvania senator, gave the name political currency in American public life across several decades. The name also appears in American musical history — "Sweet Adeline" and other parlor songs were composed by Harry Von Tilzer and Richard Gerard Arlen — and carries a faint association with the golden age of American popular song. In Irish-American communities, Arlin and Arlen functioned as subtle markers of heritage, names that retained a Celtic sound without requiring knowledge of the original Irish language.
Today Arlin occupies a quietly distinctive space in the naming landscape. It is uncommon enough that most bearers will rarely meet another, yet it is phonetically familiar — sitting comfortably alongside Arlen, Marlin, and Darlin in the register of warm, mid-century American names with Celtic undertones. Its brevity and soft ending give it a gentle strength. For parents seeking a name that is historically rooted, culturally specific, and genuinely rare without being invented, Arlin offers considerable appeal.