A distinction of Frege, a Wittgenstein-era titan: to mention a word or phrase is to speak about it, w/ at least implicit quotation marks: e.g., "Kate" is a four-letter name; to use a word or phrase is to mention its referent: e.g., Kate is by default the main character of Wittgenstein's Mistress.
footnote 7. kinda interesting to think about