An author who invents an Old Solar System planetary culture is under strong pressure to invent the names used in it.
One prime example: native names for the planets themselves. E.g. the Martian word for Mars: "Barsoom" or "Malacandra" or "Zdakash". The words had better have a good ring to them!
Harlei: And why do you call this a "significant" exception?
Stid: I reckon it's hardly a coincidence that Hamilton and Brackett, more than the other OSS writers we are considering, portray a Solar System criss-crossed by Terran ships and penetrated by Terran culture. Consequently, Eric John Stark's and Captain Future's worlds are to some degree dominated, though not permeated, by Terran power. It makes the use of Earth words for the planets less incongruous.
Zendexor: Hmm... but where's the Earth influence in The Sword of Rhiannon? None; and that's proof that even in a thoroughly Martian tale you don't have to have your Martians call Mars anything but 'Mars'.
After all, in such a narrative, speech by Martians is presumably either in an English they've learned, or in a lingo that is translated for the purposes of the story anyway. So of course the name of the planet has been translated too.
Stid: A pity that those Brackett Martians used Celtic names, though! "Rhiannon" and "Caer Dhu" on ancient Mars!! A bit of a laugh.
Zendexor: I was talking about names for the planets. Rhiannon is a person, not a planet. Caer Dhu is a stronghold. I agree, though, that their Celtic sound pulls one's imagination in an incongruous direction. But The Sword of Rhiannon is a good enough story to survive such a gaffe.
Now - going back to native names for the planets - let's start a list.
Names given by Lunarians:
Va-nah [the Moon]
Names given by Martians:
Rasoom [Mercury], Cosoom [Venus], Jasoom [Earth], Barsoom [Mars], Thuria [Phobos], Cluros [Deimos], Sassoom [Jupiter]
Names given by Venusians:
Amtor [Venus] - and that's all, because the Amtorians, beneath their cloud cover, never developed astronomy
Names given by the people of Phobos:
Names given by Jovians:
Garobus [Mars], Eurobus [Jupiter]
Names given by Callistans:
Gordrimator [Jupiter], Juruvad [Amalthea], Orovad, the "green moon" [Io], Ramavad [Europa], Imavad, the "red moon" [Ganymede], Thanator [Callisto]
Names given by both Mercurians and Uranians (the names are in common, as in the "Old Solar" names for the planets given in the C S Lewis trilogy - presumably because they are absolute expressions of the worlds' inner nature):
Valeddom [Mercury], Nuzhryven [Venus], Urom [Earth], Yyu [Luna], Zdakash [Mars], Ooranye [Uranus], Xaddanthye [Titania]
Names given by Martians and Venusians (names in common because they are in the "Old Solar" tongue):
Viritrilbia [Mercury], Perelandra [Venus], Thulcandra "the Silent Planet" [Earth], Sulva [Luna], Malacandra [Mars], Glundandra [Jupiter], Lurga [Saturn]. The Sun itself is Arbol.
There is also a world [?] called Neruval but it is not specified what, if anything, the name corresponds to in our speech.
The single mention of Neruval occurs in chapter 17 of Perelandra, when the eldila are giving their assurance that the universe is not largely an empty waste -
Be comforted, small immortals. You are not the voice that all things utter, nor is there eternal silence in the places where you cannot come. No feet have walked, nor shall, on the ice of Glund; no eye looked up from beneath the Ring of Lurga, and Iron-plain in Neruval is chaste and empty. Yet it is not for nothing that the gods walked ceaselessly around the fields of Arbol...
The context of Glund (Jupiter) and Lurga (Saturn) suggests that Neruval is also a giant planet, in which case it would have to be either Uranus or Neptune.
Either of them would fit the message, namely, that worlds which are uninhabitable by organic life are nevertheless resonant with life in a different sense.
C L Moore:
Sha-ardol [Venus], Lakkdiz [Mars]
Yllednis [the asteroid-progenitor planet mentioned in The Space Vampires]
For one way of getting names see: Never Waste a Typo.