That may have actually been (slightly?) intentional. When talking about our Sun in the greater context of stars, I've often seen it referred to as "Sol". The best immediate example I have are games like Stellaris or Elite: Dangerous which refer to our home system as the "Sol System" and our star as "Sol", but I recall hearing it in non-sci-fi contexts as well.

I'm not really sure how the etymology works out on all of that, though.

It’s from Latin for “sun”.

Which is perfect, by analogy with month and moon.

If you spoke a language where the word for sun and day were the same, you'd barely notice.

Chinese is one such language. Both “sky” and “sun” are also used for “day”

Yep!

Ming (明) is my favorite Hanzi, thanks to a lovely weekend spent at Sun-Moon Lake in Taiwan.

Also (kind of) analogous to the expression “many moons ago” referring to the cycles of the moon.

It truly seems like an awful convention compared to the common "<planet> day" or "<planet> hour".

If you call it something more verbose like <x>ian day, people are just gonna shorten it in conversation to "day" and then you end up with confusing ambiguities.

Mars day

Jupiter day

Saturn day => Saturnday => Saturday

We just need to combine English and Spanish:

Sun => Sunday

Moon (Lunar) => Lunes => Monday

Mars => Martes => Tuesday

Mercury => Miercoles => Wednesday

Jupiter (Jovian) => Jueves => Thursday

Venus => Viernes => Friday

Saturn => Saturday

You have to know your mythology well to understand that.

Tyr was the Norse god of war, so equivalent to Mars.

Wotan was an old name for Odin, who started as the messenger of the gods, like Mercury. (The connection was clearer when Tacitus was comparing German and Roman mythologies than in current Norse myths.)

Thor was the god of thunder, like Jupiter.

Frey and Freya were god and goddess of fertility, so parallel Venus.

English already has the same names. Wednesday is Woden's day. Thursday is Thor's Day, Friday is Frigg's day. These are just English translations of the planets associated with the gods.

The names of the days of the week are fairly uniform on Earth. Monday (Moon-day) = lunes (spanish) = 月曜日 (japanese - getsuyoubi, moon day). Sunday = 日曜日 (sunday, or almost "sun sun"). These came through China and are very old names -- tying the seven objects you can see move against the background stars (ignoring Uranus if you know where to look) is an idea going back the the classical era.

> These came through China and are very old names -- tying the seven objects you can see move against the background stars (ignoring Uranus if you know where to look) is an idea going back the the classical era.

Well, the Japanese weekday names come to Japanese through China. They don't originate there; the fact that they occur in the same order as the Western days of the week strongly suggests that they didn't develop independently.

The native (old) Chinese system divides months into three roughly equal 旬 periods; seven-day weeks aren't part of it.

Note for those reading my sibling comment. As https://norse-mythology.org/gods-and-creatures/the-vanir-god... points out, Frigg and Freya are ultimately the same goddess.

Mars day is great, but what do we do with the other six days of the week?

"Today," or "tosol?"