Force field

A force field was an energy barrier, the technology had many applications including use in defensive and safety systems, applications in the sciences and in holography.

Force fields were common systems aboard the starships and facilities of most advanced cultures. For instance in Federation Starfleet vessels, by the 24th century, force field generators were placed at almost every junction along corridors allowing the quick containment of personnel and substances within a limited area should it be required. The Borg were also known to use forcefields routinely in their vessels, which sometimes restricted the movements of intruders, but Borg drones were able to pass through them unhindered by adjusting the frequency of their own personnel force fields. 

Borg drones' personal force fields could similarly be adapted to block out phaser fire, so after a few shots from an enemy all drones in the vicinity would adjust their force fields to block out the weapons fire allowing them to continue their activities unhindered. The Federation have also utilised personnel force fields, generated by life support belts.