separation (n.) Look up separation at Dictionary.com
early 15c., from Old French separation, from Latin separationem (nominative separatio) noun of action from past participle stem of separare (see separate). Specific sense of "sundering of a married couple" is attested from c.1600. Separation of powers first recorded 1788, in "Federalist" (Hamilton), from French séparée de la puissance (Montesquieu, 1748). Separation anxiety first attested 1943.