(1) (Generation 4) The fourth generation of a product, typically hardware rather than software. In contrast, "4G" refers to network generations (see cellular generations).
(2) A family of smartphones from LG introduced in 2015. The premium G4 is a 5.5" phablet, while the 5.7" G4 Stylus (G Stylo in North America) includes LG's Rubberdium stylus, and the 5" G4c is the smallest model. LG offers leather-bound backs for the G4.
(4) An earlier series of Mac desktops and PowerBook portables that used the 32-bit G4 chip based on Motorola's PowerPC 7400. Introduced in 1999, G4 models were the successor to the G3 series and supported 2GB of RAM, 64-bit PCI slots and 4x AGP. The G4 CPU included the "Velocity Engine," which provided one gigaflops of floating point processing. See G5, G3 and Apple.