We've probably all wondered how a new word gets into the dictionary.

Take the word "doofus," for example, spelled d-o-o-f-u-s, meaning a stupid or incompetent person.

This word, which has been around since the late 1960's in a slang sense, made it into the Merriam-Webster's Collegiate Dictionary only in 1993.

Why did it take so long?

Well, first of all, dictionary editors like to wait at least three years to be sure a word is going to last, especially a slang word.

They don't want to put in a new word prematurely and then have to take it out in the next edition.

But even for words that aren't slang, getting into the dictionary isn't easy.

New words have to pass a lot of editorial tests, including how difficult or easy they are to look up.

There's also a limit to how thick a dictionary can be or how small its type can get before people feel they don't want to use it.

Some words have to come out before others can go in.

The Collegiate Dictionary adds about ten thousand words to every edition, but it takes out only a few hundred, so choices have to be made very carefully.