Tay can come from the River Tay in Scotland or function as a short modern name with place-based roots.
Tay is a name of elegant brevity whose origins run in several directions at once. Most anciently, the Tay is Scotland's longest and most storied river, its name derived from a Brittonic Celtic root possibly meaning "silent one" or "strong river"—the same quiet power that runs through the brooding Highland landscape it carves. The river lent its name to the Firth of Tay, the Tay Bridge (subject of William McGonagall's famously bad commemorative verse after its catastrophic 1879 collapse), and a whole geography of Scottish imagination.
As a given name, Tay operates both as a standalone identity and as a natural nickname for Taylor—itself an occupational surname from the Old French "tailleur" (cutter of cloth) that became one of the most popular given names of the 1990s and 2000s. The abbreviated Tay distills Taylor to its most essential sound, cool and unhurried, and has gained independent traction in recent years. It also resonates in East and Southeast Asian naming traditions, particularly in Thai culture, where Tay is a recognizable given name in its own right.
In contemporary American culture, Tay gained fresh visibility as an informal nickname for Taylor Swift, arguably the defining pop artist of her generation. The name fits an era that prizes minimalism and efficiency—one syllable, no ambiguity, effortlessly modern—while carrying an undercurrent of Scottish river-mist and ancient landscape for those who want it.