/ Dictionary / Index D demarcation: Meaning and Definition of Find definitions for: de•mar•ca•tion Pronunciation: (dē"mär-kā'shun), [key] — n. the determining and marking off of the boundaries of something. separation by distinct boundaries: line of demarcation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: demarcation (Thesaurus) demarcate demarcative Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language