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

visible bell
vbell
visual bell

    (Or "visual bell") A program option (whether
   in a terminal program, termcap setting, or as a
   stand-alone program) which outputs the bell character
   code as a visual signal (e.g., a flashing status bar or menu
   bar).

   Generally intended for deaf or hearing-disabled users who
   couldn't hear the normal auditory beep; also widely used by
   users who simply don't want their machines feeping at them
   or disturbing other users.

   [Implementations?]

   (1997-04-07)