Informal diminutive of Katherine, from Greek katharos meaning 'pure.'
Katty is a variant spelling of Katy or Katie, themselves diminutive forms of Katherine — one of the most enduring given names in Western history. Katherine traces back through Latin Katharina to the Greek Aikaterinē, a name whose etymology has been debated for centuries. The most widely accepted scholarly view connects it to the Greek katharos, meaning 'pure' or 'unsullied,' though an earlier version of the name may predate this Greek folk etymology and have obscure pre-Greek origins.
The connection to purity, however, became central to the name's identity through the veneration of Saint Catherine of Alexandria, a third-century martyr whose legend spread across Europe and the Byzantine world. Katty as a specific spelling carries a slightly old-fashioned English flavor, appearing in eighteenth and nineteenth-century literature and records as a familiar form of the more formal Katherine or Catherine. Characters named Katty appear in Irish and Scottish folk traditions in particular, reflecting the Gaelic tendency to render the familiar form of the name with a 'y' ending.
The name Katty Puncheon appears in some regional British folk songs; it has an earthy, no-nonsense quality that distinguishes it from the more refined Katherine. In the modern era, Katty appears most often as an intentional spelling choice — a way to preserve the familiar warmth of Katy while creating a slightly more distinctive written form. The journalist and author Katty Kay, longtime anchor for BBC World News America, has given the name contemporary professional visibility. The spelling softens the name without changing its sound, and its deep roots in the Katherine tradition give even this variant considerable historical ballast.