cropmark

/K R AA1 P M AA1 R K/
noun
  1. 1

    A sign of the former location of some feature (such as a wall or a ditch) revealed by variations in plant growth on the surface.

  2. 2

    Any of the marks placed at the corners of a form to indicate where the page is to be trimmed.

Source: https://en.wiktionary.org/wiki/cropmark