KGT p. 56:

The general term for disruptor is nISwI'. A disruptor pistol or hand-held disruptor (and there are several models of these) is a nISwI' HIch; a disruptor rifle (likewise with several models) is a nISwI' beH. Larger and more powerful disruptors are mounted on the ship, laid out as nISwI' DaH or "disruptor banks." These terms are used only for these Klingon weapons.

The more general term pu', "phaser," may also apply to the Klingon disruptor, but it is used just as often to refer to the Romulan disruptor, Federation phaser, and other similar devices. Since the word is short, pu' is heard frequently--even more frequently than nISwI'--especially in the throes of combat, in such formations as pu'HIch ("phaser pistol"), pu'beH ("phaser rifle"), pu'DaH ("phaser banks"), and even pu'beq ("phaser crew," the crew members responsible for the operation of the weapons). Despite the prevalence of the pu' words, in the strictest sense, the correct names for all of these weapons are the nISwI' forms.