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

Seven-Segment Display

    (SSD) A kind of display element consisting of seven
   independently controllable lines arranged as a rectangular figure
   eight.  A seven-segment display is the simplest device that can
   display any of the digits zero to nine (and some other characters)
   by lighting different combinations of lines.  They are often seen
   in electronic calculators or measuring equipment.

   (2013-04-27)