(də) prep. French
Of; from: used in names and phrases, as in Cyrano de Bergerac; coup de main. De combines with the masculine singular article le to form du, and with the plural article les to form des; before vowels and silent h the e is elided, as in coup d'état.

1. Away; off: deflect, decapitate.
2. Down: decline, descend.
3. Completely; utterly: derelict, denude.
4. The undoing, reversing, or ridding of (the action or condition expressed by the main element): decoding, decentralization, decarbonization. [<L de from, away, down; also <F dé- <L de-, or <OF des- <L dis- (see DIS-)]
De- may appear as a prefix in hyphemes or solidemes, with the sense of definition 4; as in: