Pardon my naivete, but what does "redbook" mean?


I'm in the market for a new CD player but I'm new to all the audiophile jargon. Is it a kind of CD or a way of judging a CD players performance? Thanks for the info
teamnokaoi
Post removed 
Or it could mean...
A pricing guide for numismatists (coin collectors)
A communist revolutionary's handbook
Zoya and Elizabeth.....thanks for the info from a neophyte. And Fatparrot...you missed "or it could be a woman's magazine"....you also missed your calling at the Comedy Club....thanks for the comedy relief!
Teamnokaoi, your comments are counter-revolutionary. Loyal revolutionary guard forces would shortly be arriving at your home to take you and your family away to a "re-education camp", except that our money is worthless, and we can't even pay them with food, since our fearless leaders have consumed it all. Long live the revolution (yeah, right,...until the next tyrannical despot in the line of murderous succession!)