juror (n.)

"one who serves on a jury," c. 1300 (late 12c. in Anglo-Latin), from Anglo-French jurour (late 13c.), Old French jureor "character witness, person who swears an oath," from Latin iuratorem (nominative iurator) "swearer, sworn census-clerk," agent noun from iurare "to swear," from ius (genitive iuris) "law" (see jurist). Meaning "one of a group selected to award prizes, etc. at a public exhibition" is from 1851; this particular use seems to have arisen with the great Industrial Exhibition held that year at the Crystal Palace in London.