A popular brand of video card, using a graphics chip by NVIDIA. The original GeForce came after the RIVA TNT card, and every NVIDIA consumer graphics card since has been a GeForce something-or-other (GeForce 2 MX, GeForce FX 5800 etc).
See our NvidiaDriverHowto page for information on setting these up under Linux.
5 pages link to GeForce: