So Darwin invented neutral selection...?

No, he invented first gear... but creationists are trying to put it in reverse.

He came up with the theory, yeah. It was around, just people didn't know about it. Evolution is the result of natural selection. It's survival of the fittest. The strongest, most attractive members of a species were more likely to survive and reproduce. This leads to desirable, useful characteristics becoming present in a species over a long period of time. I think this is what you mean. But read the bottom paragraph of this-

http://curiosity.discovery.com/topic/ecology-and-e...

Darwin didn't "invent" natural selection, he just wrote a book theorizing that natural selection is what has enabled the process of evolution to develop more and more complex/smart/strong living beings over time. Those who believe in evolution believe that it has always been around (since the "big bang," anyway) and that the process of evolution continues even to this day and we are still evolving. Natural selection is a key part of evolution because it is what weeds out those creatures that are not able to adapt to survive in the changing environment.

To answer your question more accurately; I would first like to know it's meaning.

I thought I invented neutral selection...rats!