Definition from Wiktionary, the free dictionary
See also: place holder
placeholder (plural placeholders)
- Something used or included temporarily or as a substitute for something that is not known or must remain generic; that which holds, denotes or reserves a place for something to come later.
- This is placeholder data, so you'll want to include the real numbers as soon as you have them.
2013 February 14, Scott Tobias, “A Good Day To Die Hard [film review]”, in The AV Club, archived from the original on 10 March 2016:
that which holds, denotes or reserves a place for something to come later