noun a shutter, as for a channel for molten metal.
2. shuttle ·vi to move backwards and forwards, like a shuttle.
3. shuttle ·noun the sliding thread holder in a sewing machine, which carries the lower thread through a loop of the upper thread, to make a lock stitch.
4. shuttle ·noun an instrument used in weaving for passing or shooting the thread of the woof from one side of the cloth to the other between the threads of the warp.