A security team is a squad of security personnel. They are usually assigned aboard major Starfleet ships, and carry weapons such as phasers.

Starfleet crewman Roger Lemli was a member of the security team aboard the USS Enterprise. (TOS: "The Trouble with Tribbles")

Captain Jean-Luc Picard ordered Worf to seal off deck 16 and post security teams on every access point when the Borg took over this deck. (Star Trek: First Contact)

Aboard the USS Voyager in 2375, Neelix asked security to send a team to the mess hall after The Doctor started to develop a feedback loop in his holoprogramming. (VOY: "Latent Image")