Cutting beam
From Memory Alpha, the free Star Trek reference.
A cutting beam is a beam of directed energy which is used to perform a cutting function.
Borg starships are known to have the ability to generate cutting beams of great power, strong enough to slice sections of a starship, or even a planet, open with great precision. In conjunction with the Borg tractor beam, their cutting beams are used to "scoop" pieces of ships or cities for assimilation by Borg drones and collectives. (ENT: "Regeneration"; TNG: "Q Who", "The Best of Both Worlds", "The Best of Both Worlds, Part II")
The USS Melbourne's saucer section was destroyed by a Borg cutting beam at the Battle of Wolf 359. (DS9: "Emissary")
