Exclusion; an instance of this.
Mid 17th century; earliest use found in Thomas Blount (1618–1679), antiquary and lexicographer. From classical Latin disclūsiōn-, disclūsiō state of being separated off (2nd century a.d. in Apuleius) from disclūs-, past participial stem of disclūdere + -iō.
Failure of opposing teeth to make contact (when the jaws are closed); an instance of this; (also) treatment aimed at producing this; = disocclusion . Compare "occlusion", "malocclusion".