(1) Short for Media Access Unit, an Ethernet transceiver.
(2) Short for Multistation Access Unit (also abbreviated as MSAU), a token-ring network device that physically connects network computers in a star topology while retaining the logical ring structure. One of the problems with the token-ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure. A MAU is a special type of hub.