disjunction (n.)

c. 1400, disjunccioun, "fracture" (of a bone), from Old French disjunction (13c.) and directly from Latin disiunctionem (nominative disiunctio) "separation," noun of action from past-participle stem of disiungere, from dis- (see dis-) + iungere "to join together," from nasalized form of PIE root *yeug- "to join."