demarcation

Concise Oxford English Dictionary © 2008 Oxford University Press:
demarcation/diːmɑːˈkeɪʃn/

▶noun

• 1 the action of fixing boundaries or limits.

  ■ a dividing line.

• 2 Brit. the practice of requiring that specific jobs be assigned to members of particular trade unions.

– derivatives
demarcate verb,
demarcator noun.

– origin C18: from Sp. demarcación (from demarcar ‘mark the bounds of’), orig. used with ref. to the line dividing the New World between the Spanish and Portuguese, laid down by the Pope in 1493.