de·mar·ca·tion also de·mar·ka·tion 
(dē′mär-kāshən)
(dē′mär-kāshən)n.
1. The setting or marking of boundaries or limits.
2. A separation; a distinction: a line of demarcation between two rock strata.
[Spanish demarcación, from demarcar, to mark boundaries : de-, off (from Latin dē-; see DE-) + marcar, to mark (from Italian marcare, from Old Italian, of Germanic origin; see merg- in the Appendix of Indo-European roots).]