1. The act of separating or state of being separated.
2. (Science: chemistry) The separation of a molecule into two or more fragments (atoms, molecules, ions or free radicals) produced by the absorption of light or thermal energy or by solvation.
3. (Science: psychology) a defense mechanism in which a group of mental processes are segregated from the rest of a persons mental activity in order to avoid emotional distress, as in the dissociative disorders or in which an idea or object is segregated from its emotional significance, in the first sense it is roughly equivalent to splitting, in the second, to isolation.
4. A defect of mental integration in which one or more groups of mental processes become separated off from normal consciousness and, thus separated, function as a unitary whole.
5. (Science: biology) separation of a double-stranded DNA molecule into its single strands, occurring when the hydrogen bonds connecting the two strands are broken (eg by heating).
Origin: L. Sociatio = union