What's the difference between i.e. and e.g.?
early 15c., "action of commending oneself to another," from Old French recommendation (Modern French recommandation), from Medieval Latin recommendationem (nominative recommendatio), noun of action from past participle stem of recommendare (see recommend). Meaning "act of recommending (someone or something) as worthy" is from 1570s. Letter of recommendation is from late 15c.