Origin and history of Woden

chief Teutonic god, the All-Father, a 19c. revival in reference to Scandinavian neo-paganism, from Danish, from Old Norse Oðinn, from Proto-Germanic *Wodanaz, name of the chief Germanic god (source of Old English Woden, Old High German Wuotan), from PIE *wod-eno-, *wod-ono- "raging, mad, inspired." Related: Odinism (1796 in reference to the ancient religion; by 1855 in reference to a modern Germanic revival).

fourth day of the week, Middle English Wednes-dai, from Old English wodnesdæg "Woden's day," a Germanic loan-translation of Latin dies Mercurii "day of Mercury" (compare Old Norse Oðinsdagr, Swedish Onsdag, Old Frisian Wonsdei, Middle Dutch Wudensdach). For Woden, see Odin.

Contracted pronunciation is recorded from 15c. The range of Middle English spellings is notable; Middle English Compendium lists among others wedenisdai, wedinsdai, wensdai.

The Odin-based name is missing in German (mittwoch, from Old High German mittwocha, literally "mid-week"), probably by influence of Gothic, which seems to have adopted a pure ecclesiastical (i.e. non-astrological) week from Greek missionaries. The Gothic model also seems to be the source of Polish środa, Russian sreda "Wednesday," literally "middle."

The identification of Odin, chief Germanic god, with Roman Mercury is in Tacitus but has puzzled historians. OED (1989) suggests it is because both were gods of eloquence.