noun

• The total destruction of something.
• The concealing or covering of something.
• The cancellation, erasure or deletion of something.
• (medicine) The cancellation of the function, structure, or both of a vessel or organ; for example, the occlusion of the lumen of a duct, blood vessel, or lymphatic vessel, be it solely functional (as when squeezed by nearby mass effect or inflammation) or both structural and functional (as when clogged with thrombus, embolus, or fibrosis).