An accessory available for many cameras that allows an additional battery (or possibly AA batteries) to be inserted and duplicates controls for vertical shooting.
A battery grip is an accessory available for many cameras that allows an additional battery to be inserted to extend shooting time (and often allows AA batteries to be used in place of the normal rechargeable battery through a separate battery magazine), and duplicates a selected set of controls for easier vertical shooting. A battery grip can make the camera easier to hold with larger lenses as well. Many top-of-the-line cameras, such as the Canon EOS-1D series and Nikon models designated with single digits (such as the D4), have integrated vertical grips and use a single, extra-high-capacity battery.
