The way we DETERMINE the meaning of words is how it's used by most speakers with an average level of education. This is why, in a live language meanings continuously change. We say that dead language like Latin, Sanskrit or Ancient Greek are "dead" because they don't evolve. Your example is obviously a figure of speech (metaphors). Like when somebody says "I'm all ears". Not intended to be taken literally. Metaphors are excluded from the above rule. Somebody saying "He's taller than a skyscraper" doesn't change the meaning of the word "skyscraper" when not used as a metaphor.