Aslin is likely related to the Irish Aisling, meaning dream or vision.
Aslin is most naturally understood as a variant of the Irish Gaelic name Aislinn (also spelled Aisling or Aislinn), meaning 'dream' or 'vision.' The Irish word aisling carries extraordinary cultural weight: it is the name for a specific genre of Irish poetry that flourished from the 17th through 19th centuries, in which Ireland herself appeared to the poet as a beautiful woman in a dream-vision, lamenting the loss of Gaelic civilization under English rule and prophesying eventual restoration. These poems — by Aogán Ó Rathaille, Eoghan Rua Ó Súilleabháin, and others — were acts of political resistance encoded in lyric beauty, and the word aisling became inseparable from Irish longing and hope.
As a given name, Aislinn and its variants emerged from this literary tradition, carrying the dual meaning of the private dream and the national vision. The anglicized spelling Aslin smooths the name for non-Irish readers while preserving its essential sound — the soft initial vowel, the gentle 'sl' consonant cluster, the open final syllable. It is a name that sounds like the experience it describes: soft, hovering between sleep and waking, full of imagery just beyond the grasp of words.
S. Lewis's Narnia — a name derived from the Turkish word for lion — and in some communities may be influenced by that association. But its heart remains the Celtic dream tradition: a name for a child who arrives as a hoped-for vision, embodying the old Gaelic sense that the boundary between the seen and the unseen world is always, beautifully, permeable.