Wiktionary
accelerated graphics port
n. (context computing English) A high-speed port used to attach a display adapter to a personal computer.
Wikipedia
Accelerated Graphics Port
The Accelerated Graphics Port (often shortened to AGP) is a high-speed point-to-point channel for attaching a video card to a computer system, primarily to assist in the acceleration of 3D computer graphics. It was originally designed as a successor to PCI-type connections for video cards. Since 2004, AGP has been progressively phased out in favor of PCI Express (PCIe); by mid-2008, PCI Express cards dominated the market and only a few AGP models were available.