(covers information from several alternate timelines)
Weapons array was a term used to describe the interconnected series of starship-mounted offensive technologies used by a particular vessel.
In 2151, the Enterprise NX-01 managed to disable the shields of an attacking Malurian starship by beaming an antimatter reactor into close proximity to the Malurians and detonating it with a torpedo. Sub-Commander T'Pol then ordered Lieutenant Malcolm Reed to disable the ship's weapons array. (ENT: "Civilization")
In 2368, while investigating recovered wreckage of a Vulcan ship, Lieutenant Commander La Forge initially suspected that the debris in the possession of the USS Enterprise was part of a weapons array, but the Vulcans reported no stolen weapons. (TNG: "Unification I")
In 2370, the powering-up of the weapons array of a rogue Borg vessel was detected by the crew of the Enterprise, allowing Doctor Beverly Crusher, who was in temporary command at the time, to raise the ship's shields in time to defend itself from an attack. (TNG: "Descent, Part II")
Later that year, while the Enterprise was engaged in battle with a Ferengi starship, Captain Picard ordered Lieutenant Worf to target the Ferengis' weapons array only, in order to minimize the damage that would be inflicted on the rest of the ship. (TNG: "Force of Nature")
That same year, while testing a new photon torpedo guidance system, Lieutenant Worf performed thirteen separate tests of the Enterprise's weapons array to determine why a fired torpedo had veered off course, but was unable to find an explanation. (TNG: "Genesis")
Commander Benjamin Sisko, aboard the runabout USS Rio Grande, managed to disable the power couplings to the weapons array of a Maquis vessel with which he was engaged in combat. This forced the pilot of the Maquis ship, former Starfleet officer, Lieutenant Commander Calvin Hudson, to make a strategic retreat. (DS9: "The Maquis, Part II")
In 2371, the USS Voyager's weapons array took a direct hit while engaged in battle with a number of Kazon vessels. Chakotay subsequently decided to beam his entire Maquis crew over to Voyager, and use his ship to ram one of the Kazon vessels, inflicting serious damage. (VOY: "Caretaker")
Later that year, while trapped in a delusional state, The Doctor fantasized that he was the last person left on board Voyager after a Kazon attack. Upon asking the computer for a damage report, he learned that, amongst other problems, the ship's weapons array was offline. (VOY: "Projections")
That same year, a Changeling infiltrator managed to bring the weapons array of the USS Defiant online and take control of the ship, with the intention of attacking a Tzenkethi outpost and starting a war between them and the Federation. The Changeling was eventually foiled by the crew of the Defiant. (DS9: "The Adversary")
Following the emergence of the Dominion threat, Deep Space 9 underwent a massive overhaul of its weapons array in 2371. It was first used in combat against the Klingons in the First Battle of Deep Space 9 and a year later during the Second Battle of Deep Space 9 against the Dominion. (DS9: "The Way of the Warrior", "Call to Arms")
In 2372, while attempting to find a vulnerability in an alien vessel, Lieutenant Tuvok detected a slight phase retraction when auxiliary power was transferred to the aliens' aft weapons systems, and that a covariant phaser pulse to their aft control systems might disable the vessels' entire phaser array. When testing this theory in combat, however, it did not work. (VOY: "Parturition")
Later that year, while engaged in battle with Kazon ships, Voyager's weapons array was disabled, as were their shields.
While Voyager was engaged in battle with the Botha, they managed to fire upon one of the enemy vessels' weapons array, but not enough to severely damage it. It was later determined, however, that the enemy vessels were not actually real, and that the Botha were using their telepathic abilities to create illusory starships. (VOY: "Persistence of Vision")
That same year, in a parallel universe, a Klingon officer reported to Regent Worf that a new vessel was being constructed by Terran rebels that displayed "an impressive weapons array." (DS9: "Shattered Mirror")