The Free On-line Dictionary of Computing (30 December 2018):

ribbon cable

    A type of flat multicore cable with cores
   positioned side-by-side, making it quick and relatively easy
   to clamp an Insulation Displacement Connector (IDC) across
   all cores.

   Ribbon cables typically have grey insulation with cores on a
   0.050" pitch and a red stripe marking Pin 1.  They are less
   resilient than screened, multicore cable and are usually used
   inside equipment where little movement or plugging and
   unplugging are expected.  A common use is connecting a disk
   drive to the motherboard in a PC.

   (2007-07-21)