Wiktionary
draw a line
vb. (context idiomatic English) To delimit a boundary or border.
WordNet
draw a line
v. reasonably object (to) or set a limit (on); "I draw the line when it comes to lending money to friends!" [syn: draw the line]
Usage examples of "draw a line".
You could draw a line with a pencil on one side, a waterless barren.
If you look at the Narriz harbor and draw a line east to Bokagul, you have the line Augustus must defend.
Therefore, if we must draw a line, it ought to be drawn conservatively.
If you draw a line from the Kukulcan pyramid to the center point of the impact crater, the angle measures 23.
In the old days it was thought you had to draw a line in front of the chicken with chalk, but modern masters of the art have learned you can dispense with the props.