An Etymological Dictionary of the German Language/Annotated/decken
decken, verb, ‘to cover, screen,’ from the equivalent Modern High German dęcken, Old High German dęcchan; the latter (with cch- from kj) from *þakjan, which was most likely the Gothic form; compare Anglo-Saxon þęccan (obsolete in English); Old Icelandic þekja, ‘to cover.’ þakjan is a derivative of the Aryan root teg (discussed under Dach), which appears with the same meaning in Latin tegere, Greek σ-τέγεω, Sanscrit sthagâmi. A strong verb þekan corresponding to tego, στέγω, is is nowhere recorded within the Teutonic group; the weak verb has assumed its function.