Technobabble refers to meaningless scientific - sounding jargon that is often inserted to make a character sound smart, or make a technology sound advanced or complicated.
Star Trek is particularly notorious for this, so much so in fact that it has spawned the specialized word "Treknobabble" for instances of technobabble in Star Trek.
Technobabble can also refer to a device or weapon with an unknown mechanism which is not based on direct energy transfer and blatantly violates the laws of physics.
An example of technobabble:
http://www.youtube.com/watch?v=naXLxNX4UZc