Disruptor arrays were weapons equipped on Klingon and Romulan starships.
The first encounter of Humans with disruptor arrays was Enterprise NX-01 encountering a Klingon Raptor-class vessel in 2151. (ENT: "Sleeping Dogs")
Three years later, Enterprise encountered a D5-class battle cruiser with a dorsal disruptor array. (ENT: "Divergence")
By 2368, the Federation was aware that Breen ships also carried disruptors. (TNG: "Hero Worship")
Romulan D'deridex-class warbirds carried at least one disruptor array on the forward hull of the ship. (TNG: "The Enemy"; VOY: "Message in a Bottle")
A D5-class with a dorsal disruptor array.
A Romulan vessel firing disruptor pulses
A Romulan nose-mounted disruptor