Who are the Guardians of the Galaxy

Before getting strange, please read the question. :)

I just watched the movie, twice and they talk about someone being a guardian of the galaxy in a couple of occasions. And around the end of the movie Quill says something like: "we are the guardian of the Galaxy".

but nowhere in the movie seems to be explained who those Guardians are, if they are a real association or if it is just a name they give themselves during the movie or if it just a teaser developed during the movie.

they are clearly not part of any association and when they leave together at the end of the movie they are just friends leaving together.

So my question is, in the MCU at the moment the movie take place, is there something called Guardians of the Galaxy that are recognized and/or known?