What's the difference between i.e. and e.g.?
1580s, "believer in a mystical religious doctrine of spiritual knowledge," from Late Latin Gnosticus, from Late Greek Gnostikos, noun use of adj. gnostikos "knowing, able to discern," from gnostos "knowable," from gignoskein "to learn, to come to know" (see know). Applied to various early Christian sects that claimed direct personal knowledge beyond the Gospel or the Church hierarchy.