The premise of this question is based on a few faulty assumptions.
Turbo has 2 correct definitions, and one odd tacked on thing that almost counts as a 3rd definition.
Definition 1, meaning "big or fast". Much as you can have turbocapitalism (an accelerated/exaggerated form of capitalism), you can have turbolasers. These would presumably have a higher rate of fire than regular lasers. Or the lasers could travel faster. Or just be bigger.
Definition 2: "Drawing power from a turbine." Power generation in the star wars universe, as in ours, almost all comes from a turbine (for real world universe, that is coal, gas, hydro, wind, some solar thermal, fission and fusion. It excludes the most basic of solar thermal, and all solar photovoltaic, as well as rockets. Batteries are often thought of as being a turbineless form of power production, but ultimately they store energy produced by another source, likely a turbo one. There can be chemical energy stored and released, such as in gunpowder, without the need for a turbine.
Half Definition 3: Related to a turbo charger in a car. This is really just definition 2 again, because a turbocharger in a car uses a turbine, and that is where the name comes from.
So under definition one, a turbolaser is just one that fires faster than the competition.
Under definition 2, if it one that draws its power from a turbine.
So that leads us to the question of where non turbo lasers draw their power from. As it turns out, they are produced from directly igniting tibanna gas, which is a very concentrated energy source analogous to gunpowder.
This would lead me to the conclusion that Turbolasers have to be plugged in to some sort of generator (likely fusion in the SW universe), contrasting them to more portable lasers.
Further evidence for this is provided here, indicating that the Death Star superlasers are indeed powered by the reactors, and that they are essentially a scaled up turbolaser.
Interestingly, the US Navy actually has a turbolaser in operation. We as a society are so far away from having an energy production/storage source good enough to allow for laser weapons that aren't turbolasers.
I just realised I should edit in a point here. I dispute the assumption that we can be certain that one stole from other other, because the physical concept of a turbolaser, as well as the name, are not particularly unusual or weird. This, combined with the other answer showing a very short timeframe between the two (presumably indicating that BSG script writing was undertaken, or at least started before Star Wars was released) implies to me the more likely answer is that both came up with this idea independently.