Emily Dickinson Lexicon

DE-MARK-A'TION, n. [Sp. demarcacion, from demarcar; de and marcar, to mark; marca, a mark; Port. demarcar. See Mark.]

1. The act of marking, or of ascertaining and setting a limit.
2. A limit or bound ascertained and fixed; line of separation marked or determined. The speculative line of demarkation, where obedience ought to end and resistance begin, is faint, obscure, and not easily definable. – Burke.