The Collaborative International Dictionary of English v.0.48:

De- \De-\
   A prefix from Latin de down, from, away; as in debark,
   decline, decease, deduct, decamp. In words from the French it
   is equivalent to Latin dis- apart, away; or sometimes to de.
   Cf. Dis-. It is negative and opposite in derange, deform,
   destroy, etc. It is intensive in deprave, despoil, declare,
   desolate, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

DE
    n 1: a Mid-Atlantic state; one of the original 13 colonies [syn:
         Delaware, Diamond State, First State, DE]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DE
       DatenElement (HBCI)


The Free On-line Dictionary of Computing (30 December 2018):

de

    The country code for Germany.

   (1999-01-27)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

DE. A preposition used in many Latin phrases as, de bone esse, de bonis
non.