"session of a law court," c. 1300 (attested from mid-12c. in Anglo-Latin), from Old French assise "session, sitting of a court" (12c.), noun use of fem. past participle of asseoir "to cause to sit," from Latin assidere/adsidere "to sit beside" (and thus to assist in the office of a judge), "sit with in counsel or office," from ad "to" (see ad-) + sedere "to sit," from PIE root *sed- (1) "to sit." Originally "all legal proceedings of the nature of inquests or recognitions;" hence sessions held periodically in each county of England to administer civil and criminal justice.