A bipod is an attachment for either a photographical device or a weapon that creates a steady plane for whatever it may be attached. It provides significant stability along two axes of motion (side-to-side, and up-and-down). The concept for a bipod dates back to pre-20th century times, and is still used today by agencies such as NASA.
Bipod comes from the Latin and Greek roots bi and pod, meaning "two" and "foot, or feet" respectively.
On firearms, bipods are commonly used on rifles and machine guns to provide a forward rest and reduce motion. They are also seen on other long-barrelled weapons. Bipods permit operators to easily rest a weapon on objects, like the ground or a wall, reducing their fatigue and increasing accuracy and stability. Bipods can be of fixed or adjustable length. Some can be tilted and also have their tilting point close to the barrel's central axis, allowing the weapon to tilt left and right. Some designs also allow the weapon to be rotated side-to-side. There are three ways for bipods to be folded: away from the shooter, towards the shooter, or into a vertical foregrip.
The simple design is also included in circumstances such as NASA’s space shuttle launches. NASA honed the idea in a different way, they used the bipod system to create a launch pad for their rocket ships to launch off, it basically acted as a track for the rocket to propel on. The bipod launch system revolutionized the way space shuttles lift off into space, in a straight vertical line. More recently, rockets have scaled to a much smaller size, thus leading to a new hobby of model rocket building. The design of the toy is very simple, it includes a silver launch pad at the bottom and two metal rods that act as a bipod for the scaled rocket to launch.
Most squad automatic weapons, such as this FN Minimi, have a bipod to increase accuracy in full-automatic mode.
A Sako TRG sniper rifle on its standard factory bipod and its monopod under the stock.