What's the difference between i.e. and e.g.?
mid-13c., "having merit," from worth (n.) + -y (2). Old English had weorþful in this sense. Attested from c.1300 as a noun meaning "person of merit" (especially in Nine Worthies, famous men of history and legend: Joshua, David, Judas Maccabæus, Hector, Alexander, Julius Cæsar, Arthur, Charlemagne, Godfrey of Bouillon -- three Jews, three gentiles, three Christians).