1640s, from Medieval Latin occlusionem (nominative occlusio), noun of action from past participle stem of Latin occludere (see occlude). Dentistry sense is from 1880.
occlusion oc·clu·sion (ə-klōō'zhən)
n.
The act of occluding or the state of being occluded.
An obstruction or a closure of a body passage.
Any contact between the cutting or chewing surfaces of opposing teeth.
The alignment of the teeth of the upper and lower jaws when brought together.
The absorption of a gas or other substance, as by a metal.
The inclusion of one substance within another.