(v): keep from happening or arising; make impossible
(v): render unsuitable for passage
(v): block passage through
(v): obstruct access to
(v): block passage through
(v): impose a blockade on
(v): surround so as to force to give up
(n): a war measure that isolates some area of importance to the enemy
(n): a military engagement
(n): prevents access or progress
(n): any structure that makes progress difficult
