Nonprintable is self explanatory... Inkjet printable means that you can print text/graphics directly to the surface of the disc with a capable inkjet printer (Epson R200 or R300 series in US and Canon abroad). Inkjet printable discs come in white surface and silver surface. Thermal printable is the same with a thermal printer (Casio has a couple of models). Lightscribe printable discs require a lightscribe enabled drive to "Burn" text/graphics to the disc (the two manufacturers that immediately come to mind are from BenQ and HP)... Pay particular attention to what kind of printable disc it is. A lot of ads will just say "silver printable." This usually is referring to thermal printable. Inkjet printable and lightscribe media will usually be noted prominently in the description as will whether the media is hub printable (print almost to center).
