[from LISP 1.5 (and later,
MacLISP)] To output a newline. Now rare as jargon, though
still used as techspeak in Common LISP. It is a contraction of
`TERminate PRInt line', named for the fact that, on some early OSes
and hardware, no characters would be printed until a complete line
was formed, so this operation terminated the line and emitted the
output.