dissociation

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The act of dissociating or the condition of having been dissociated.
2. n. Chemistry The process by which the action of a solvent or a change in physical condition, as in pressure or temperature, causes a molecule to split into simpler groups of atoms, single atoms, or ions.
3. n. Chemistry The separation of an electrolyte into ions of opposite charge.
4. n. Psychiatry A psychological defense mechanism in which specific, anxiety-provoking thoughts, emotions, or physical sensations are separated from the rest of the psyche.

Century Dictionary and Cyclopedia

1. n. The severance of association or connection; separation; disunion.
2. n. Specifically In chem., the resolution of more complex into simpler molecules by the action of heat. Also called thermolysis. Dissociation is applied by some authors to cases where the dissociated gases recombine when the temperature falls, and thermolysis where the gases do not spontaneously recombine on cooling. Also disassociation.
3. n. In psychology: The disjunction of an associative connection, as by lapse of memory or by intercurrent associations, by the selective process of active attention, etc.
4. n. A minor degree of the disintegration or disaggregation of consciousness, as it is termed, which culminates in the phenomena of dual or multiple personality.

Wiktionary

1. n. The act of dissociating or disuniting; a state of separation; disunion.
2. n. chemistry The process by which a compound body breaks up into simpler constituents; said particularly of the action of heat on gaseous or volatile substances.
3. n. psychology A defence mechanism where certain thoughts or mental processes are compartmentalised in order to avoid emotional stress to the conscious mind.

GNU Webster's 1913

1. n. The act of dissociating or disuniting; a state of separation; disunion.
2. n. (Chem.) The process by which a compound body breaks up into simpler constituents; -- said particularly of the action of heat on gaseous or volatile substances

WordNet 3.0

1. n. a state in which some integrated part of a person's life becomes separated from the rest of the personality and functions independently
2. n. the act of removing from association
3. n. (chemistry) the temporary or reversible process in which a molecule or ion is broken down into smaller molecules or ions