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

terpri

   /ter'pree/ TERminate PRInt line.  [LISP 1.5 and later,
   MacLISP] To output a newline.  Still used in Common
   LISP.  On some early operating systems and hardware, no
   characters would be printed until a complete line was formed,
   so this operation terminated the line and emitted the output.

   [Jargon File]

   (1996-06-24)