de- / Indo-European roots
Demonstrative stem, base of prepositions and adverbs.
1. Form *dō (possibly instrumental).
a. (i) to, too from Old English tō, to; (ii) tsimmes from Old High German zuo, ze, to; (iii) tattoo1 from Middle Dutch toe, to, shut. (i)-(iii) all from Germanic *tō;
b. Italic *dō in compound *kwām-dō (see kwo-).
2. Form *dē (possibly instrumental), perhaps source of forms meaning "from, out of"
a. de- from Latin dē, dē-, from;
b. deteriorate from Latin dēterior, worse, from suffixed form *dē-tero-;
c. compound *dē-bel-i- (see bel-);
d. Celtic *dī, from, in compound *eks-dī-sedo- (see sed-).
[Pokorny de- 181.]