PRO PHOTOGRAPHERS: What Does PRIME LENS mean?

I want to get a better lens for my Nikon D90.It came with 18-105 mm lens. I've read about a 50 mm f/1.4 g ED nikkor lens. Description says "Prime lens". What does it mean? Better quality? If I buy it, can I get better quality instead 18-105?

What the difference between all those lenses (besides the price)?

Hi. Prime lens means its a "fixed focal length" lens, which basically means it _cannot_ zoom. That's all there's to it.
Because of it is fixed and can't zoom its construction is alot simpler to manufacture, which means prime lenses can be alot more light sensitive (bigger aperterures / lower f/numbers) and sharper.

If you think that only a pro could answer this then you really do not have a very high opinion of normal photographers.
Why not just go out and learn stuff instead of asking stupid questions in a way that suggests that you would not understand an accurate answer?