Topics Language, art and culture

Where did the days of the week get their names?

Most of the days of the week are named after the Sun, the Moon and a set of gods. The planetary day names are tied to the seven bright bodies ancient observers could see moving against the stars: the Sun, the Moon, Mars, Mercury, Jupiter, Venus and Saturn. In the Roman world each day was linked to one of them, and the names spread from there.

What makes it interesting is the translation. Germanic speakers, including the ancestors of English speakers, matched Roman gods to gods of their own. Tuesday, Wednesday, Thursday and Friday come from Old English names tied to Tiw, Woden, Thor and Frige, while Saturday keeps its Roman root in Saturn. Why Saturn was kept is not fully settled, though it is often suggested that no obvious Germanic match was found. The origin of the seven-day week itself is debated, since several older cultures counted days in groups.

An episode would walk through the week day by day, then look at what other languages did with the same idea. Spanish and French keep the Roman pattern from Monday to Friday, while Portuguese numbers its weekdays (segunda-feira, terça-feira, and so on) rather than naming them after gods. bre is an app whose hosts are AI, so they can be wrong, and the episode says where the history is uncertain.

What a bre episode would cover

An outline of the episode bre would make for this question. Every episode is written fresh when you ask, so yours will differ.

  1. Seven bodies in the skyWhy ancient observers counted seven wandering lights, and how the Sun, the Moon and five planets became a calendar rhythm in the Roman world.
  2. Sunday and MondayThe most straightforward days: the Sun and the Moon, which reflect a Germanic translation of the Roman day names.
  3. Tuesday to Friday: gods swappedHow Mars, Mercury, Jupiter and Venus were matched with Tiw, Woden, Thor and Frige, and why such matches were always an interpretation, not a perfect fit.
  4. Saturday, the Roman holdoutIn English, Saturday still points to Saturn. Why it kept the Roman name is uncertain, and the episode says so rather than pretending to know.
  5. Other languages, other choicesLundi and lunes come from the Moon, and mardi to vendredi from Roman gods. In French and Spanish, Sunday became the Lord's day and Saturday (samedi, sábado) comes from the Sabbath.
  6. What the names tell us about language contactHow day names show peoples borrowing, translating and adapting each other's ideas, and what that suggests about how words travel.

How the episode might open

A sample exchange between two of bre’s AI hosts, bre and Tess. Both are AI; this is written by AI, as every bre episode is.

  1. breAI host

    Okay, the question everyone half-asks on a Monday: why is it called that, and who decided Thursday belongs to a god with a hammer?

  2. TessAI host

    Okay, but real talk. I use these words forty times a week and have no idea what they mean. Is there an actual story?

  3. breAI host

    There is, and it starts with the sky. People watched seven bright things move: the Sun, the Moon, and five planets. Each got a day.

  4. TessAI host

    So Sunday is the Sun and Monday is the Moon. That part sounds easy.

  5. breAI host

    Easiest part, yes, and it reflects a Germanic translation of the Roman names. The trickier part is Tuesday. Romans linked that day to Mars, and Germanic speakers swapped in their own war god, Tiw.

  6. TessAI host

    So they translated gods like a phrasebook?

  7. breAI host

    Roughly, yes. Wednesday became Woden's day, Thursday Thor's, Friday Frige's. Saturday is the odd one, probably because no neat match was found, though nobody can say for sure.

  8. TessAI host

    Fine. Here's my trick: Thursday is Thor's day, so think thunder. Start with Sunday and work down, and I'll stop you if I'm lost.

Questions people also ask

Which days of the week are named after gods?
In English, Tuesday, Wednesday, Thursday and Friday come from Old English names tied to the gods Tiw, Woden, Thor and Frige. Saturday comes from the Roman god Saturn. Sunday and Monday are named for the Sun and the Moon.
Why does Saturday still use a Roman name?
Saturday comes from Saturn, a Roman god. Why it kept the Roman name is not settled. It is often suggested that Germanic speakers had no clear matching god, but historians treat that as a likely explanation rather than a proven one.
Do other languages name days the same way?
Many do, with differences. French lundi and Spanish lunes come from the Moon, and mardi to vendredi (martes to viernes in Spanish) come from Roman gods. Dimanche and domingo come from the Lord's day, and samedi and sábado come from the Sabbath.
Why are there seven days in a week?
The exact origin is debated. Seven matches the number of bright wandering bodies ancient observers tracked, and several older cultures used seven-day or similar cycles. Historians do not agree on a single source, so the explanation is a mix of astronomy, religion and habit.

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bre’s hosts are AI, and every episode is generated, so they can be wrong: check anything that matters. This page outlines what an episode would cover. It is for interest and learning, not medical, financial or legal advice.