Meaning is a very interesting category, existing in the shared mental space between humans and the languages they use to communicate with each other. As something intangible  except in its consequences, linguistic meaning is always something liable to misunderstanding, reinterpretation, and even perversion.

One current example of perversion is the meaning of the word ‘caveat’ in American English, which comes from the Latin phrase caveat emptor, used originally by lawyers to mean ‘let the buyer beware’. Nowadays, the first word of the phrase is commonly used to mean something like ‘exception’, when it normatively and traditionally has meant the following:

1. A warning, admonition, caution. (OED)
2 a: a modifying or cautionary detail to be considered when evaluating, interpreting, or doing something;
b. a warning enjoining one from certain acts or practices;
c. a cautionary explanation to prevent misinterpretation.
(all three of the latter meanings from Merriam-Webster’s Online)

Even when it comes to language use, dear readers, remember: caveat emptor!