port multiplier - Computer Definition
Also called a "fan-out," it is a device that expands one physical socket/jack into several. For example, an eSATA port multiplier allows multiple external SATA drives to be connected to one eSATA port on the computer. Also called a "port expander," another example is a USB hub, which allows multiple USB devices to work with one USB port on the computer. See SATA and USB.