Demarcation – A line or rule that shows the limits of something
The mark on the ground was the location (demarcation) of the boundary between the enemy.
Examples of demarcation in a sentence
The demarcation between North and South Korea is The Korean Demilitarized Zone.
You need a demarcation line in the middle of the two teams if you want to play tug of war.
It was hard to draw clear lines of demarcation between the two territories.