title conferred on some prelates and dignitaries of the papal court and household, 1640s, from Italian monsignore "my lord," formed on model of French monseigneur (see monseigneur) from equivalent elements in Italian.
"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 of all legal proceedings of the nature of inquests or recognitions; hence its use for sessions held periodically in each county of England to administer civil and criminal justice.
1520s, from French suprême (15c.) and directly from Latin supremus "highest," superlative of superus "situated above," from super "above" (from PIE root *uper "over"). Supreme Being "God" first attested 1690s; Supreme Court is from 1689.
"one who appeals from a lower to a higher court," 1610s, from Anglo-French, French appellant, noun use of present participle of French appeller "make an appeal" (Old French apeler), from Latin appellare "appeal to" (see appeal (v.)).
"where accused stands in court," 1580s, probably originally rogue's slang, from Flemish dok "pen or cage for animals," which is of unknown origin.
in reference to special court proceedings, late 13c., from Anglo-French lete, Anglo-Latin leta, of unknown origin; OED suggests possible connection to let (v.).