Merriam-Webster Collegiate Dictionary - dissociation

 noun  Date: 1611  1. the act or process of dissociating ; the state of being dissociated: as  a. the process by which a chemical combination breaks up into simpler constituents; especially one that results from the action of energy (as heat) on a gas or of a solvent on a dissolved substance  b. the separation of whole segments of the personality (as in multiple personality disorder) or of discrete mental processes (as in the schizophrenias) from the mainstream of consciousness or of behavior  2. the property inherent in some biological stocks (as of certain bacteria) of differentiating into two or more distinct and relatively permanent strains; also such a strain  • dissociative adjective