Origin: before 1050;Middle Englishtewesday,Old Englishtīwesdæg (cognate with Old High Germanzīestac,Old Norsetȳsdagr), orig. phrase Tīwes daeg Tiu's day, translating Latindiēs Mārtis day of Mars. See Tiu, 's1, day
O.E. Tiwesdæg, from Tiwes, gen. of Tiw "Tiu," from P.Gmc. *Tiwaz "god of the sky," differentiated specifically as Tiu, ancient Gmc. god of war, from PIE base *dyeu- "to shine" (see diurnal). Cf. O.N. tysdagr, Swed. tisdag, O.H.G. ziestag. The day name (second element
dæg, see day) is a translation of L. dies Martis (cf. It. martedi, Fr. Mardi) "Day of Mars," from the Roman god of war, who was identified with Gmc. Tiw (though etymologically Tiw is related to Zeus), itself a loan-translation of Gk. Areos hemera. In cognate Ger. Dienstag and Du. Dinstag, the first element would appear to be Gmc. ding, þing "public assembly," but it is now thought to be from Thinxus, one of the names of the war-god in L. inscriptions.