Short for Accelerated Hub Architecture (also called Intel Hub Architecture), Intel introduced this hub architecture starting with the 820 chipset. The hub architecture divides control between a memory controller hub (MCH) that supports memory and AGP and an I/O controller hub (ICH) that supports PCI, USB, sound, IDE and LAN. The word hub in Intel Hub Architecture refers to the north and south bridges in a chipset. Intel has replaced those two terms with the word hub.
[Image Source: INSIDE THE PC, Nigel S. Smith, University of Cambridge Computing Service]