Laser weapon
From Memory Alpha, the free Star Trek reference
Laser weapons are weapons that utilize lasers, a directed light technology that compresses photon particles into a beam that can have heat and blast effects. While many spacefaring lifeforms utilize lasers as optical data networks, few continuously use laser weapons, since a variety of more exotic and powerful weapon effectiveness is achieved by using weapons that duplicate lasers in design, but utilize different subatomic particles to create the beam.
Starfleet crews used laser weapons in 2254, around the time USS Enterprise visited Talos IV. Landing parties carried laser pistols and large laser cannons were available as heavy artillery. (TOS: "The Cage")
In 2268, Uhura wondered why the Klingons didn't provide the villagers of Neural with more advanced weaponry such as old-style hand lasers. (TOS: "A Private Little War")
Starfleet Regulations called for a Federation starship to go to yellow alert when targeted by laser weapons from another vessel, although 24th century USS Enterprise-D captain Jean-Luc Picard thought the rule was outdated, since the laser weapons of an Altec ship were incapable of even penetrating the navigational deflectors. Picard also noted that they could fire until their lasers run dry and still wouldn't cause any damage to the Enterprise. (TNG: "The Outrageous Okona")
[edit] Background
In The Making of Star Trek, Gene Roddenberry stated that two days into the filming of the second pilot, they realized that three years later people are going to say "Oh, come on, lasers can't do that" so the term was substituted with phaser.
