The name Wednesday continues Middle English Wednesdei. Old English still had wōdnesdæg, which would be continued as *Wodnesday (but Old Frisian has an attested wednesdei). By the early 13th century, the i-mutated form was introduced unetymologically.
The name is a calque of the Latin dies Mercurii "day of Mercury", reflecting the fact that the Germanic god Woden (Wodanaz or Odin) during the Roman era was interpreted as "Germanic Mercury".
The Latin name dates to the late 2nd or early 3rd century. It is a calque of Greek ἡμέρα Ἕρμου heméra Hérmou, a term first attested, together with the system of naming the seven weekdays after the seven classical planets, in the Anthologiarum by Vettius Valens (ca. AD 170).
The Latin name is reflected directly in the weekday name in Romance languages: mercredi (French), mercoledì (Italian), miércoles (Spanish), miercuri (Romanian), dimecres (Catalan), Marcuri or Mercuri (Corsican), dies Mercurii (Latin). The German name for the day, Mittwoch (literally: "mid-week"), replaced the former name Wodanstag ("Wodan's day") in the tenth century. Most Slavic languages follow this pattern and use derivations of "the middle" (Bulgarian сряда sryada, Croatian srijeda, Czech středa, Macedonian среда sreda, Polish środa, Russian среда sredá, Serbian среда/sreda or cриједа/srijeda, Slovak streda, Slovene sreda, Ukrainian середа sereda). The Finnish name is Keskiviikko ("middle of the week"), as is the Icelandic name: Miðvikudagur, and the Faroese name: Mikudagur ("Mid-week day"),. Some dialects of Faroese have Ónsdagur, though, which shares etymology with Wednesday.Danish, Dansk Onsdag, ("Ons-dag" = Odens/Odins dag/day, same in Swedish).wednesday is called 'budhwar in hindi.
Portuguese uses the word quarta-feira, meaning "fourth day". While in Greek the word is Tetarti (Τετάρτη) meaning simply "fourth." Similarly, Arabic أربعاء means "fourth", Hebrew רביעי means "fourth" and Persian چهارشنبه means "fourth day." Yet the name for the day in Estonian is (kolmapäev) meaning "third day), in Lithuanian, (trečiadienis), and in Mandarin Chinese, 星期三 (xīngqīsān), means "day three", as Sunday is unnumbered.