"Nomenclature's washin' away / It's washing us all away" ~ Andrew Bird
"So how does a word get into a dictionary? It gets in because we use it and we keep using it, and dictionary editors are paying attention to us. If you're thinking, 'But that lets all of us decide what words mean,' I would say, 'Yes it does, and it always has.' Dictionaries are a wonderful guide and resource, but there is no objective dictionary authority out there that is the final arbiter about what words mean. If a community of speakers is using a word and knows what it means, it's real. That word might be slangy, that word might be informal, that word might be a word that you think is illogical or unnecessary, but that word that we're using, that word is real."
See also: "20 Words that Once Meant Something Very Different," IDEAS.TED.COM