Laser pistol

A Laser pistol is a type of hand-held energy weapon used in the mid-23rd century, the successor of the Phase pistol and predecessor of the Type-2 phaser.

Laser pistols features a grip and twist function to change the setting, they fire blue or magenta beams (presumably at different settings) and were capable of forced chamber overloads. (TOS episode: The Cage, Flesh of my Flesh, The Fallen, et al.)

Background
The laser pistol was the first hand held weapon in Star Trek production history, however in-universe, following Star Trek: Enterprise's introduction of Phase pistols, they might be seen as a step back in technology from the obviously named forerunner of hand phasers. However Laser pistols have also been shown used alongside Phaser rifles in Where No Man Has Gone Before and several Star Trek: Early Voyages comics suggesting they are perhaps an intermediate step used until Phaser technology was available in a more compact form.

The name is also problematic as lasers compared to the phased energy of both phase pistols and phasers would be a step back, this would probabley suggest that Laser pistols are not lasers under our current definition of the term, or that Laser pistols are not lasers at all and just named such as slang or maybe an acronym.