The authority you need here to coin a word is gonna be a dictionary, and before we talk about how to get into one, we need to deconstruct the idea of what a dictionary is. Which may seem a little dumb, but I promise you, most lexicographers (dictionary-writers) have exactly the opposite view on language than people think they do.
Dictionaries are mostly used by prescriptivists, that is, people looking for the One True Spelling (or Meaning) of a particular word. The dictionary is correct and flawless and complete, and deviations from it are by definition (heh) wrong. Hence the idea that any word not in the dictionary is not a “real” word.
But dictonaries are mostly made by descriptivists. Rather than prescribing correct usages and spellings, lexicographers are describing the language as they find it. They take in thousands of examples of words in use, whether from well-established academic texts or from awesome pop song mashups, and try to write a definition that covers those usages. And since people are constantly using language in new ways, the dictionary is never complete and never totally correct.
Came across a blog with some nice, concise posts about language and linguistics. Check it out!
Repeating for emphasis: "And since people are constantly using language in new ways, the dictionary is never complete and never totally correct."(via intosnarkness)