occlusion (Noun) — Closure or blockage (as of a blood vessel).
occlusion (Noun) — (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft.
occlusion (Noun) — (dentistry) the normal spatial relation of the teeth when the jaws are closed.
occlusion (Noun) — An obstruction in a pipe or tube. ex. "we had to call a plumber to clear out the occlusion in the drainpipe"
occlusion (Noun) — The act of blocking.