A disruptor cannon was a directed energy cannon weapon commonly used aboard starships of many different species.
Klingon 22nd century Klingon Birds-of-Prey were equipped with an impressive arsenal, for the time, and included wing-mounted (and belly-mounted) disruptor cannons and photon torpedo launchers. (ENT: "Borderland") These cannons were capable of firing in either disruptor pulse or beam modes. (ENT: "The Augments")
These weapons were also found in later designs of Klingon Birds-of-Prey, Negh'Var warships, Vor'cha-class attack cruisers, and K't'inga-class battle cruisers. (DS9: "Blood Oath", "The Way of the Warrior"; TNG: "Redemption"; SNW: "Subspace Rhapsody")
According to the Star Trek: Deep Space Nine Technical Manual, disruptor weapons generally carry more energy than standard phaser weapons, but are more lacking in accuracy and fast discharge.