Force field

Forcefields are designed to prevent an individual or their weapons fire from passing through a certain point, much like Shields on Starships. They are utilized by many races as security barriers.

Ancient
The Ancients used forcefields to protect their Stargates and to seal people in certain sections of their ships. They are also used in the Atlantis brig and can prevent even Wraith from escaping. Forcefields are also used in Atlantis's quarantine rooms to hold in Asurans.

Lantean personal forcefields are able to block anything except air from passing though them and are formed skin-tight to the user's body. They can block the effects of all weapons fire and fully dampen large falls until their power cells deplete.

Tok'ra
The Tok'ra use an advanced form of one-way forcefield to keep their prisoners inside their cells whilst allowing weapons fire to enter the cell should it be necessary.

Tau'ri
The Tau'ri have been able to produce a plasma force field with the specific function of acting as a temperature barrier for a matter bridge designed by Rodney McKay, but stolen by Malcolm Tunney.

Tollan
The Tollan force fields are used to protect key areas of the government buildings.

Goa'uld
The Goa'uld used a massive forcefield to block passage to the Stargate when SGs 3, 5, 6 and 11 were sent to retrieve SG-1 from Hathor's SGC mock-up. Because of its size, a huge generator was required to power it. The forcefield was deactivated when C4 charges were remotely detonated inside the generator.

Hand device's can also project a personal forcefield around a person that blocks impact with fast moving objects and energy, but allows slow moving ones through.

Wraith
The Wraith use forcefields to protect landed ships from hijack and also to hold Asurans who could easily escape from normal Wraith cells.