Dissociation (n.) is a defense mechanism whereby one loses track of time or of one's person.
Dissociation (n.) is a rending of the mind by dynamic forces within itself.
Dissociation (n.) is an active defense phenomenon. When the integrity of the overall system is threatened, subsystems of ideas/wishes/memories/thoughts are forcibly repressed, dissociated, or split off.
Dissociation (n.) is not the mark of a failing, but of a mind at work on other matters at that particular moment, more vital than consciousness.
Dissociation (n.) can run through the ego itself: faced with an unwelcome reality, it both accepts and disavows it at once, two contrary attitudes living side by side in a rift that never heals but widens.