What's the difference between i.e. and e.g.?
late 15c., "act of avenging, revenge," from Latin vindicationem (nominative vindicatio) "act of claiming or avenging," from vindicare "to set free, lay claim to, assert, avenge" (related to vindicta "revenge"), probably from vim dicare "to show authority," from vim, accusative of vis "force" + root of dicere "to say" (see diction). Meaning "justification by proof, defense against censure" is attested from 1640s.