Megawatt means a really big watt -- that's a lot of power.
Mazer rhymes with laser -- sounds reasonable to me. Bring it!
Mazer is a microwave laser.
Originally Laser was light amplified whatsits doohickey acronym, and radio lasers were termed rasers, and UV lasers were UVasers, phased lasers were phasers and such.
Eventually the only term that stuck was Laser.
*shrugs*
I dunno why.
But a megawatt mazer would be quite a thing to behold, or not behold actually as it would be invisible until it hit something.