It's Sunday...
The word for this day of the week, Sunday, comes from the Middle English (a form of the English language that was spoken from 1066 until the late 15th century) word sunnenday, which comes from the Old English (or Anglo-Saxon, the earliest recorded form of the English language) word sunnandæg. The English derivations come from the Latin diēs sōlis, literally “sun’s day.”
The Babylonians were the ones who started the seven-day week; they brought it to the Latin-speaking Romans, who named each day after a god. Germanic and Nordic people did the same, but with their own corresponding gods: Tiw, Woden, Thor, Frig, and Saturn, ...
In Germanic pre-Christian religions, the sun was represented by Sol, a woman who rode a chariot carrying the sun across the sky.
With Christianity, Latin-derived Romance languages changed “sun’s day” to “lord’s day” (domingo in Spanish, domenica in Italian, and dimanche in French); the word remained “Sun’s day” in the languages that would eventually become modern English.
Here's an idiom with Sunday:
a month of Sundays
What does it mean?
It means an indeterminately great length of time.
Do you know any other idioms with Sunday or its equivalent in another language and culture?
