G3 - Computer Definition
(1) (Generation 3) The third generation of a product, typically hardware rather than software. See 3G.
(2) A series of Macintosh desktops and PowerBook portables from Apple that were based on the PowerPC 750 chip. Models were introduced in 1997 starting at 233 MHz. See G4.
(4) (Group 3) See fax/modem.