[lutusp]

> Not according to dictionary.com - that says that the purpose of the dictionary is to provide information on meaning and correct usage of the word.

Wait, think a minute. That description exactly corresponds with what I said. The "correct" usage of a word is precisely, exactly what the speaker thinks it means, at that moment in time.

If a dictionary listed a definition that was not in use by anyone, that would be different -- that would be incorrect.

> Also, Wikipedia refers to two types of dictionary: prescriptive and descriptive.

Yes, and there are no prescriptive dictionaries, at least not in English. The French have one, created by the Académie française:

http://en.wikipedia.org/wiki/Acad%C3%A9mie_fran%C3%A7aise

Apart from the French example, it seems telling people how to use words has fallen out of fashion, giving way to another example of evolution by natural selection.