demarcation (noun) - the act, process, or result of marking off a boundary; an established line of separation [dee-mahr-key-shuhn]
BREAKDOWN: DE- (down) + MARC- (boundary) + -ATION (action)
to demarcate means to set apart or establish a boundary (also demark)
“The country was made without lines of demarcation, and it is no man's business to divide it.” —Chief Joseph