demarcation

Etymology

First recorded c.1752, from Spanish línea de demarcación and/or Portuguese linha de demarcação, the demarcation line laid down by the Pope on May 4, 1493, dividing the New World between Spain and Portugal on a line 100 leagues west of the Cape Verde Islands. Both derive from demarcar, from de- + marcar (“to mark”), from Italian marcare, from the same Germanic root as march.

noun

1. The act of marking off a boundary or setting a limit, notably by belligerents signing a treaty or ceasefire.
2. A limit thus fixed, in full demarcation line.
3. Any strictly defined separation.
   There is an alleged, in fact somewhat artificial demarcation in the type of work done by members of different trade unions.
   In the sea there is no demarcation between the hunter and the hunted, as there is on the African plains. 1983, Richard Ellis, The Book of Sharks, Knopf, page 7