What's the difference between i.e. and e.g.?
early 14c., "to estimate the worth of, to appraise," from Old French ponderer "to weigh, poise" (14c., Modern French pondérer) and directly from Latin ponderare "ponder, consider, reflect," literally "to weigh," from pondus (genitive ponderis) "weigh" (see pound (n.1)). Meaning "to weigh a matter mentally" is attested from late 14c. Related: Pondered; pondering; ponderation.