For some reason, way back in 1934, Websters managed to include a made-up word (I guess that all words are made-up in a sense, but you know what I mean). It wasn't until five years later that somebody actually noticed the word "dord" - which isn't a real word.
On the plus side, if you came up with your own word now, you could refer to it as a "dord". Are we confused yet? I am.