CD/DAC's are CD players that have digital inputs.  You can also think of them as DAC's that have CD drawers.  Some are built more for one or the other - for example the Rega Isis is more of a dedicated CD player that also has a single 16 bit USB input while the Audio Research CD9/DAC is really more of a dedicated DAC with a CD drawer because it has a full array of digital inputs and adjustable digital filters.