What's the difference between i.e. and e.g.?
early 15c., from Church Latin catechizare "to teach by word of mouth" (also source of French catéchiser, Spanish catequizar, Italian catechizzare), from Greek katekhizein "teach orally, instruct by word of mouth," from katekhein "to resound" (see catechesis). Related: Catechized; catechizing.