PDU - Protocol Data Unit or Power Distribution Unit
(1) Short for Protocol Data Unit. The term used to describe data as it moves from one layer of the OSI model to another. In this reference, PDU is often used synonymously with packet.
(2) Short for Power Distribution Unit. An electrical device used to control the distribution of power to individual loads. The PDU may be a stand-alone controlled device or it may be integrated directly into the UPS (uninterruptible power supply).