The example in question: the term "chemist" has been used to describe pharmacists since the middle ages, because in the middle ages and perhaps until a century or so ago, the pharmacist literally was the chemist who synthesized the substances you purchased from him. This is no longer the case in any way at all, and yet the term remains in common use to refer to pharmacists.
I can't think of any other distinct examples off the top of my head. "Sinister", maybe? It used to literally described left-handed people because the association between left-handedness and evil was so strong as to be built into the language, and of course, since that association has largely disappeared, the word now only invokes its abstract meaning of "evil".
Edit: so, it seems like the phenomenon in question is kind of like the verbal equivalent of a skeuomorph. I wonder if there's a term for that specifically, but I don't see it mentioned in any of the number of similar threads.
