What's the difference between i.e. and e.g.?
late 14c., "one who pleads or argues for a cause," from Anglo-French oratour (Modern French orateur), from Latin orator "speaker," from orare "to speak, speak before a court or assembly, pray, plead," from PIE root *or- "to pronounce a ritual formula" (cf. Sanskrit aryanti "they praise," Homeric Greek are, Attic ara "prayer," Hittite ariya- "to ask the oracle," aruwai- "to revere, worship"). Meaning "public speaker" is attested from early 15c.