As a girl's name this is a pet form of Jacqueline, as in the case of Jackie Kennedy Onassis (1929–94). It was originally a boy's name, a pet form of Jack. The racing driver Jackie Stewart (b. 1939) was originally named John Young Stewart.
Southern Italian: occupational name from maniscalco ‘marshall’, altered from marescalco by folk etymology, probably influenced by mano ‘hand’, from medieval Latin mariscalcus, marescalcus. Compare Marshall.