Kirstie f
Scottish: pet form of KIRSTIN (SEE Kirstin), now quite commonly used as an independent given name in the rest of the English-speaking world as well as in Scotland.
Variants: Kirsty; Chirsty (the usual spelling in the Highlands); Curstaidh, Ciorstiadh, Curstag, Ciorstag (Gaelic).
First names dictionary. 2012.