1603, from Fr. détail, from O.Fr. detail "small piece or quantity," from detaillier "cut in pieces," from de- "entirely" + taillier "to cut in pieces." Modern sense is from Fr. en détail "piece by piece, item by item" (as opposed to en gros), a commercial term used where we would today use retail. Military sense is 1708, from notion of "distribution in detail of the daily orders first given in general," including assignment of specific duties. The verb is from 1637.