The days of the week in the languages I know a little resemble English in their etymology:
- Sunday = sun’s day. The German sonntag means sun day. The French dimanche derives from the Old French for day of the Lord (dies dominica), as does the Spanish domingo.
- Monday = moon day. The German montag, French lundi, and Spanish lunes derive from “moon.”
- Tuesday = Tīw’s day, from the Germanic god of war. The German dienstag, according to Wiktionary, comes from “Thingsus-dagaz (Day of Thingsus)…the attested Latin name of a Germanic God, who may or may not be the same as Tiw.” The French mardi and Spanish martes derive from Mars, the Roman god of war.
- Wednesday = Wotan’s day, from Scandinavian god Odin, the god of the hunt. The French mercredi and Spanish miercoles are what linguists call calques, “a word or phrase borrowed from another language by literal, word-for-word, or root-for-root translation.” The word being translated is Mercury, the Roman god of many things, including financial gain, commerce, eloquence, messages, communication, travelers, boundaries, luck, trickery, and thieves.
- Thursday = Thor’s day, from the Norse god of violent weather. The German donnerstag means thunder day. The French jeudi and Spanish jueves drive from Jupiter, the Roman king of gods and the god of thunder and lightning.
- Friday = after the Germanic goddess Frigga, the wife of Odin and the goddess of married love. The German freitag has the same etymology. The French vendredi and the Spanish viernes derive from Venus, the Roman god of love.
- Saturday = Saturn’s day, from the Roman Saturn, the god of wealth, agriculture, and time. The German samstag, French, samedi and Spanish sábado (and, by the way, the Hebrew shabát) all derive from words for sabbath, i.e., the seventh day of the week, starting with Sunday, and a day of rest.
Irish is a bit different:
- Sunday: An Domhnach (un doo-knock), from domhnach, lord’s day
- Monday: An Luan (un loo-in), from luain, hard work
- Tuesday: An Mháirt (un whort), from Máirt, Mars
- Wednesday: An Chéadaoin (un kay-deen), from céad (“first”) + aoine (“fast”), i.e., the first fast of the week
- Thursday: An Déardaoin (un deer-dean), from dé (“day”) + idir (“between”) + dhá (“two”) + aoine (“fast”) i.e., the day between two fasts
- Friday: An Aoine (un ee-nuh), from aoine (“fast)
- Saturday: An Satharn (un sah-rin), from Satharn, Saturn
Laethanta na Seachtaine (lay-un-tuh nuh shock-tuh-nuh) = the days of the week.