barrier
bar.ri.er \'bar-e--*r\ n [ME barrere, fr. MF barriere, fr. barre] 1a: a material object or set of objects that separates, demarcates, or serv es as a barricade 1b: an extension of the antarctic continental ice sheet into the sea restin g partly on the bottom pl, often cap 2: a medieval war game in which combatants fight on foot with a fence or ra iling between them 3: the movable gate or device at the starting line in a racetrack 4: something immaterial that impedes or separates 5: a factor that tends to restrict the free movement and mingling of indivu als or populations
Webster's English Dictionary