I'm looking for a word to describe a particular phenomenon, and I thought you all might be able to help.
Let's say an author from an earlier time period uses a term in a sense that's appropriate to that author's time period. Then, the author dies and the language evolves, or new technologies are invented. Modern readers or audiences encounter the term used by the author and incorrectly think it means something different than what the author could have possibly intended.
For example, one of the witches in Macbeth shows that she has "a pilot's thumb." The word pilot meant (and still means) someone who steers a ship. But most modern audiences are familiar with the word as meaning someone who flies an airplane, obviously not what Shakespeare meant.
I don't think this is technically an anachronism, and even if it is, I'd prefer to find a different word. "Anachronism" is generally used to describe instances where Shakespeare himself uses something appropriate to his own time in a play set before it would have been appropriate, such as the clock striking in Julius Caesar.
What I'm describing isn't a mistake; it's an accident of history. If no such word exists, I am considering coining the word "retrochronism." But is there an existing word I can use instead?