oc·clu·sion / əˈkloōzhən/ • n. 1. Med. the blockage or closing of a blood vessel or hollow organ. ∎ Phonet. the momentary closure of the passage of breath during the articulation of a consonant.2. Meteorol. a process in which the cold front of a rotating low pressure system overtakes the warm front, forcing the warm air upward above a wedge of cold air. ∎  an occluded front.3. Dentistry the position of the teeth when the jaws are closed.DERIVATIVES: oc·clu·sive / -siv/ adj.

occlusion The stage in the development of a frontal depression during which the warm-sector air is gradually lifted from the ground and above the colder air. The word is used to describe an occluded front. An occlusion may be a ‘warm occlusion’, such that warmer air follows the frontal system, or a ‘cold occlusion’, such that colder air follows in the rear. A ‘warm occlusion’ has characteristics similar to those of a warm front, but there is an upper cold front ahead and aloft, which brings showers from cumulus and cumulonimbus cloud. A ‘cold occlusion’ exhibits cold-front features, but is preceded by warm-front cloud types. Occlusions formed in the later stages in the development of travelling depressions commonly cross north-western Europe, especially the ‘warm’ type in winter and the ‘cold’ type in summer.

occlusion Stage in the development of a frontal depression during which the warm-sector air is gradually lifted from the ground and above the colder air. The word is used to describe an occluded front. An occlusion may be a ‘warm occlusion’ such that warmer air follows the frontal system, or a ‘cold occlusion’, such that colder air follows in the rear. A ‘warm occlusion’ has characteristics similar to those of a warm front, but there is an upper cold front ahead and aloft which brings showers from cumulus and cumulonimbus cloud. A ‘cold occlusion’ exhibits cold-front features, but is preceded by warm-front cloud types. Occlusions formed in the later stages in the development of travelling depressions commonly cross north-western Europe, especially the ‘warm’ type in winter and the ‘cold’ type in summer.

occlusion (ŏ-kloo-zhŏn) n.
1. the closing or obstruction of a hollow organ or part.

2. (in dentistry) the relation of the upper and lower teeth when they are in contact. See also malocclusion.