occlusion

noun oc·clu·sion \ ə-ˈklü-zhən \

Editor's Note: What Do the Words occlusion, recluse, seclusion, and exclude Have in Common?

Definition of occlusion

1 : the act of occluding : the state of being occluded: such as

a : the complete obstruction of the breath passage in the articulation of a speech sound

b : the bringing of the opposing surfaces of the teeth of the two jaws into contact; also : the relation between the surfaces when in contact

c : the inclusion or sorption of gas trapped during solidification of a material

2 : the front formed by a cold front overtaking a warm front and lifting the warm air above the earth's surface

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Recent Examples of occlusion from the Web

That paradox gets to the nub of this administration’s fraught relationship with ventilation and occlusion.

— katy waldman, Slate Magazine, "What “transparency” means to the Trump administration.," 24 July 2017
The occlusion was at first subtle and indeed novel, the sort of anomaly that breathes new life into an old warhorse.

— andrew kahn, Slate Magazine, "A review of the solar eclipse of 2017.," 21 Aug. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'occlusion.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

What Do the Words occlusion, recluse, seclusion, and exclude Have in Common?

Occlusion is a descendant of the Latin verb occludere, meaning "to close up." "Occludere" in turn comes from the prefix ob-, here meaning "in the way," and the verb claudere, meaning "to close or shut." "Occlusion" is one of many English terms derived from "claudere." Some others are "recluse," "seclusion," and "exclude." An occlusion occurs when something has been closed up or blocked off. Almost all heart attacks are the result of the occlusion of a coronary (heart) artery by a blood clot. When a person's upper and lower teeth form a "malocclusion," they close incorrectly or badly. An occlusion, or occluded front, happens when a fast-moving cold front overtakes a slow-moving warm front and slides underneath it, lifting the warm air and blocking its movement.