Demarcation – A line or rule that shows the limits of something

(Pronounced dee-mahr-kay-shuhn)

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.