Phasers were a type of weapon. Phaser was an acronym for Perpetually Heat-Activated Sonic-Emmitted Ray. They differed from the usual "laser" weapons in that they did not rapidly shoot out gas-induced plasma beams, but instead shot long beams of pure radio-active heat/light rays activated by a special type of sonic conductor. They would have been at a significant disadvantage against plasma laser weapons because the beams were a lot slower and caused a lot less damage. It is possible these were the forerunners of the modern laser guns, but it has never been specified by any historian when phasers were actually used galaxy-wide. Bounty hunters often preferred to use them as sniper rifles because they were lighter weight then the plasma-beam sniper rifles and a lot easier to handle, but finding one was very difficult. Phaser weapons were exceedingly rare and worth a lot of money as relics.