Casey \c(a)-sey\ as a girl's name (also used as boy's name Casey), is pronounced KAY-see. It is of Irish and Gaelic origin, and the meaning of Casey is "alert, watchful". From the male Gaelic name Cathasaigh. Also variant of Cassie and diminutive of Acacia. Made famous by the popular song about the heroism of Luther Casey Jones, a US engine driver who gave his life to save the lives of his passengers. His nickname was derived from his home town, spelled Cayce.
Casey has 57 variant forms: Cacey, Caci, Cacia, Cacie, Cacy, Caisee, Caisey, Caisi, Caisie, Cascy, Casee, Casen, Casi, Casie, Cass, Casse, Cassee, Cassey, Cassye, Casy, Cayce, Caycee, Caycey, Cayci, Caycie, Cayse, Caysee, Caysey, Caysi, Caysie, Cazzi, Kace, Kacee, Kacey, Kaci, Kacie, Kacy, Kacye, Kacyee, Kaissie, Kasci, Kasee, Kasey, Kasi, Kasie, Kayce, Kaycee, Kaycey, Kayci, Kaycie, Kayse, Kaysee, Kaysey, Kaysi, Kaysie, Kaysy and Kaysyee.