There are basically two schools of thought, one representing a prescriptive approach to language and embodied by the Académie Française, and the other, a descriptive approach to language typified by the Oxford English Dictionary.
I prefer the OED approach myself, which is much more in accord with the Lucretian view of language--a view that sees it as naturally and gradually developing and changing over time. In this view there is no authority. The Oxford English Dictionary is unusually thorough, running to twenty volumes in print, but its purpose is to record and document words rather than to narrowly define them. When a new word comes into common usage and has staying power, the OED will generally record it. The Académie Française will often reject them, and propose a different usage that is more properly French.
Asking whether words have meaning is to me rather like asking if a thing has value. The value of something is settled by what someone will trade for it. The meaning of words is settled by what people will commonly understand by them.