Pink Floyd isn't a what, it's a who. Pink Floyd is a fictional character created by the band of the same name.
I highly recommend EVERYONE listen to their album "The Wall". It's not a traditional music album, it's a story, it's a lifestyle. For those that enjoy it, I suggest renting the movie "Pink Floyd: The Wall". It's pretty crazy, but lets you visualize the story.
Pink Floyd is epic, nothing will ever be like them again.