Nit pick: I do not like the abbreviation "mrs" for Mars, from an etymological point of view. The root of the name of the Roman god is Mart-. The "-s" is not a

Nit pick: I do not like the abbreviation "mrs" for Mars, from an etymological point of view. The root of the name of the Roman god is Mart-. The "-s" is not a part of the name. It is the marker of the nominative case, like in "John's" the "'s" is the marker of the genitive case. "Mart-" was a stem ending in a consonant, so the case marker was attached directly to the stem, without a thematic vowel like in the most frequent Latin words. So the nominative of "Mart-" was "Marts". The Latins found difficult to pronounce "-ts", so in all such words "-ts" has been simplified to "-s", resulting in "Mars". English has the habit to borrow Latin words in their nominative-case form, because this was their traditional dictionary form. I consider this habit as bad, but this would be a longer discussion, so English has settled for the form "Mars". In Latin, in most other noun cases or in the derived words the complete name "Mart" was present, for instance in the adjective "martial", which has also been borrowed in English, or in the genitive form "Martius", which has become English "March" (and "Martius" is actually the name of the planet in Latin, because the planet Mars was not the god Mars, but the planet of the god Mars). In conclusion, I consider that the correct abbreviation for the planet Mars is "mrt", not "mrs", which has a spurious "s". There are other languages than English, e.g. many Romance languages, where the name of the planet is derived from "Mart", not from "Mars". In the Romance languages, the nouns inherited from Latin are normally derived from their accusative-case form, not from the nominative-case form. Only for nouns that have not been inherited, but which have been reintroduced by scholars, it is common to use a form derived from the nominative case of the dictionaries. In Latin, the complete name of the planet Mars was "stella Martius", the star of Mars. In ancient Latin or Greek, "planet" was not used as a noun, but as an adjective for "stella" or "aster" (star), to distinguish the wandering stars from the normal fixed stars.