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

dual ported

   A term used to describe memory integrated circuits which can
   be accessed simultaneously via two independent address and
   data busses.

   Dual ported memory is often used in video display hardware,
   especially in conjunction with Video Random Access Memory
   (VRAM).  The two ports allow the video display hardware to
   read memory to display the contents on screen at the same time
   as the CPU writes data to other areas of the same memory.  In
   single-ported memory these two processes cannot occur
   simultanteously, the CPU must wait, thus resulting in slower
   access times.  Cycle stealing is one technique used to avoid
   this in single-ported video memory.

   (1995-01-12)