Hey everyone, today I was learning the vocabulary item 海王星 (Neptune, かいおうせい) which literally translates into “the ocean god star”. I thought this was really cool, since in ancient Roman mythology Neptune was the god of the ocean as well! This coincidence, of the star being named after “the same” god twice seemed almost too good to be true. This got me really excited about 海王星 and I did some research about it and learned some new things I thought I’d share here with you all!
During my googling my bubble of excitement was slightly burst, as I found out that prior to 1846, Neptune had actually never been formally discovered. In fact, Neptune is so dim it’s not visible to the naked eye, and couldn’t be discovered until the invention of the telescope. There is some evidence that already in the 1600s and later, Galileo Galilei and other scientists had been able to observe Neptune, but it was only in 1846 that Neptune was formally discovered by Johann Gottfried Galle and Heinrich Louis d’Arrest, based on predictions by the Frenchman Urbain Le Verrier (If you’re interested in more details, I thought the wikipedia article was really interesting!)
Anyways, because of it’s late discovery, it’s name was greatly debated, and finally everyone decided on Neptune. Here comes the interesting part, in many languages today, even those completely unrelated to the Roman-Greek language/cultures, a variant of Neptune, god of the ocean, is being used! This name was quite literally borrowed into Chinese first, and the into Japanese, and this is what is called a “calque” in linguistics, and according to wiktionary is defined as:
A word or phrase in a language formed by word-for-word or morpheme-by-morpheme translation of a word in another language.
Or accrding to the corresponding wikipedia page:
A calque or loan translation is a word or phrase borrowed from another language by literal, word-for-word or root-for-root translation.
So to conclude, 海王星 and Neptune were (unfortunately) not independently named after the god of the ocean in Japanese and the Western world, but the Japanese name for the planet is in fact derived by way of a calque.
Anyways, I thought this was really interesting to learn about, some linguistics, some history, some science. I hope you enjoyed it, and I’m curious to hear if you guys have heard of any other examples of these so called calques!
On a final note, a little joke for my fellow Pokemon fans! 
they both surely comes from Roman deities) with the exception of Sunday: