"PDU" is internationalstandardscomitteespeak for packet. See also: packet. [Source: RFC1392
(PDU) (n.) The ISO/OSI term for packet. A PDU is a data object that is exchanged by protocol machines (entities) within a particular layer. A protocol data unit consists of both protocol control information (PCI) and user data.
"PDU" is "international standards comittee speak" for packet. See also: packet.