Likely a modern blend of Ed and Lynn elements, with possible echoes of Welsh name forms.
Edlyn weaves together two strands of Old English naming tradition. The "Ed-" prefix comes from the Old English element "ead," meaning wealth, fortune, or prosperity — one of the most productive roots in Anglo-Saxon naming, giving rise to Edward, Edmund, Edgar, Edwin, and Edith. It was the name-element of kings: Edward the Confessor, Edgar the Peaceful, Edmund Ironside — rulers who shaped early English identity.
The "-lyn" suffix, though it sounds modern, has roots in the Old English "lind" (gentle, tender, flexible as a linden tree) or functions as a feminine diminutive across Celtic and Germanic traditions. Edith — the closest well-known relative — was borne by one of England's great literary figures, Edith Wharton, who dissected American aristocracy with surgical precision, and by the French chanteuse Édith Piaf, whose voice became synonymous with longing and resilience. Edlyn can be understood as a quieter, more contemporary sibling to Edith: same Old English root and sense of feminine grace, different phonetic shape.
It began appearing in American records in the early 20th century, likely as a creative elaboration by parents who wanted the "Ed-" heritage in a softer form. Edlyn occupies a warm, underused corner of the naming landscape — old enough to feel authentic, rare enough to feel personal. Its meaning — something like "prosperous and tender" — is a genuinely lovely combination, and its sound, with the soft "d" giving way to the musical "-lyn," is quietly beautiful.