Dictionaries come in all shapes and sizes, for all sorts of intended audiences. Size and audience are determined by individual publishers, and indeed the finished product is shaped by all sorts of market forces. And makers of dictionaries – lexicographers – are of course human; what gets into dictionaries has historically been subject to the individual foibles of lexicographers, not to mention the mores of society.

it was typical for dictionaries not to have taboo words like f*ck, much less its derivatives f*cking, f*ck up, f*ckable, f*ck all, and f*cker, all of which can be found today in the Concise Oxford English Dictionary; but until the 1970s, dictionaries avoided words that might offend. It is perhaps safe to say that individual or societal foibles play less of a role in dictionarymaking today, but it’s still a good idea to keep in mind that neither lexicographers nor the dictionaries they create are infallible.

Our first problem with giving final authority for wordhood to the dictionary, then, follows from the very concrete and temporal nature of dictionaries: if you look up a word in a pocket dictionary, or even a standard college desk dictionary, and it isn’t listed, you might still have the nagging suspicion that a bigger dictionary or a more specialized dictionary might list the word. But even if you check the largest available dictionary – say, for English the Oxford English Dictionary On-line – or the most complete technical dictionary in a particular field, can you be sure that a word that’s not listed isn’t a word? Maybe it’s too new a word to have gotten into the dictionary yet.