Definition of "seal off" [seal off]

• Make tight; secure against leakage (verb)
• Impose a blockade on (verb)

WordNet. Princeton University. 2010.

• "The ridge could support a fleshy valve though apparently no scientist has dissected an Aldabran tortoise to find out, which might seal off the olfactory chamber at will."
• "Why did the United States military—the most powerful armed force in history—not seal off the Tora Bora region, instead relying only on a small contingent of American Special Forces on the ground?"
• "We could, of course, turn the entire search over to Allenby, leaving his soldiers and police to seal off the area and do a house-by-house search, but none of us seriously considered that option; in that we were agreed."