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

line editor

    An early kind of text editor suited to use on a
   teletype.  The user enters editing commands which apply to
   the current line or some given range of lines.  These include
   moving forward and backward through the buffer, inserting and
   deleting lines, substituting a string for a pattern match, and
   printing lines.  Visual feedback is restricted to explicitly
   requesting the display of one or more lines, in contrast to a
   screen editor.

   ed is Unix's line editor.

   (1999-03-01)