The Collaborative International Dictionary of English v.0.48:

Disjunction \Dis*junc"tion\, n. [L. disjunctio.]
   1. The act of disjoining; disunion; separation; a parting;
      as, the disjunction of soul and body.
      [1913 Webster]

   2. A disjunctive proposition. --Coleridge.
      [1913 Webster]

WordNet (r) 3.0 (2006):

disjunction
    n 1: state of being disconnected [syn: disjunction,
         disjuncture, disconnection, disconnectedness] [ant:
         connectedness, connection, link]
    2: the act of breaking a connection [syn: disconnection,
       disjunction]