Noun
1. closure or blockage (as of a blood vessel)
2. (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
3. (dentistry) the normal spatial relation of the teeth when the jaws are closed
4. an obstruction in a pipe or tube;
"we had to call a plumber to clear out the blockage in the drainpipe"5. the act of blocking