What's the difference between i.e. and e.g.?
c.1300, "means of living, subsistence, livelihood," from Old French sustenance (French soutenance), from Late Latin sustinentia "endurance," from Latin sustinens, present participle of sustinere (see sustain). Meaning "action of sustaining life by food" is from late 14c. Sense of "nourishment" is recorded from late 15c.