Everything we humans do is based on our Interpretations of the world around us. We Observe, see Patterns as we interpret them, and then we either call them facts or interpretations. Facts imply there is something absolute that cannot be denied, while "interpretation" implies a view on some aspect of reality, much like the number six can be mistaken for the number nine when you look at it from the other side.
Let's for instance consider the letter sequence "Alien", simply because that is the movie from 1979 which I am now watching on the side. It is a classic, making the word "alien" synonymous to "extraterrestrial and evil" for many movie-watchers. Good thing there were also movies like "ET" that focused on good aliens...
Another thing about the word alien and its meaning is context: as long as there are borders on Earth, the word will have a second meaning, which keeps us humans divided.