What's the difference between i.e. and e.g.?
late 14c., from Latin amphitheatrum, from Greek amphitheatron "double theater, amphitheater," neuter of amphitheatros "with spectators all around," from amphi- "on both sides" (see amphi-) + theatron "theater" (see theater). Classical theaters were semi-circles, thus two together made an amphi-theater.