Originally Posted by jaqua99
Completely not the point. The point I am making, is that The Other, a being who is probably at least 1,000 years old, referred to it as "The Tesseract". I don't think he called it that just because the humans call it that. According to The Other, and Thanos, the cube is called the tesseract, and due to their age, it has been called that for a long time.
So, again, how people of earth learn the "correct" name of it?
At the beginning of CATFA, Schmidt told the elderly man hiding the Tesseract that it was the jewel of Odin's treasure room. The Asgardians had visited Earth -- in fact, Tonsberg, Norway where the Cube was found -- and obviously told people there somethings about the artifact that were passed down along with it. The cube's name (tesseract) was known because humans had been told it.
Additionally, the word tesseract is a geometrical term for a 4-dimensional hypercube. Which is (sort of) what the Tesseract in the MCU is, except that it's also a receptacle for energy from outside this universe.