The word "fro" being used to describe a hairstyle suddenly reminded me that "fro" as in "to and fro" is what's called a "fossil word" -- used only in that idiomatic context.  My invented name for such a "revived" word is pleasing, but may imply that the word was being used for its original meaning all along before it was rediscovered by anthropologists.  I don't know of any examples of that, but do we need to save "coelacanth word" in case one is miraculously found?  Another example of a fossil word reappearing is "shebang", used for the programming sequence #!  rather than the idiom "the whole shebang".  Can you identify any more of these formerly-fossilized words?

Happy Thanksgiving to those of my friends who currently live in America!

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Not quite the same thing, but as an undergrad major in both comp sci and english lit, I was delighted to tell my old english professor about "vax" and "vaxen," possibly the first new use of this plural inflection in centuries.