Many times, people observing a club or tournament game think that players must be making up words, or that any word that's ever been used is somehow legitimate. While that's understandable, it simply isn't true. There are fewer than 100,000 words in the official dictionary. That makes it a very good college level dictionary, but falls far short of what's found in unabridged dictionaries. There is a reason so many strange words are often seen in a game, but it's not because of the dictionary. Rather, it's because of the need to maximize one's score, and the best way to do that is to learn as many words as possible, even if they aren't part of one's everyday vocabulary.

Something can be said for allowing any dictionary to be used to determine the legitimacy of words. That's how players first play the game, and the element of mystery provided by such practice can be fun. Most players, however, probably find that more frustrating than fun. Everyone has their own peculiar word knowledge, and when words they know to be legitimate aren't found in the dictionary being used, it's deflating, at the least. Just about any word one person finds strange or mystifying, another person can and has used. That should be obvious, but it's often overlooked or dismissed when debates arise about words.

So, what to do? Use an unabridged dictionary, allowing just about every word known in the English language? Or go the other way, and use a newspaper dictionary, limiting the words to a typical high school graduate's vocabulary? The former is somewhat impractical, at least when computer word judging is unavailable. The sheer size, weight and cost of unabridged dictionaries makes them difficult to use anywhere but in the home. Also, the task of learning all known words, for those who want to excel, is probably impossible. On the other hand, a dictionary with a very limited number of words would probably be found to be too frustrating.

In the end, a compromise was reached, and the Official Scrabble^® Players Dictionary was born. The OSPD has gone through several revisions over the years, but it has provided a breadth and stability to the game's allowable words satisfactory to most players. That hasn't stopped vigorous and ongoing debates about the legitimacy of this or that word, but it has stopped arguments about what dictionary will be used in club and tournament play, which is no small thing.

The OSPD, as mentioned in the opening paragraph, is a very good college level dictionary, not for its definitions but for its word content. That's because it is made up of words found in a limited (by the NSA Dictionary Committee) number of college level reference dictionaries. By including all words found in at least one of these dictionaries, the OSPD is more comprehensive than any single collegiate dictionary, yet much more concise than an unabridged dictionary. The task of learning most or all of the allowable words is still enormous, but not impossible for those with time and inclination to do so.

Because our language is ever-evolving, the OSPD does get revised. Every 5-10 years, newer words that have been listed in the source dictionaries are also added to the OSPD. Due to the extreme difficulties in unlearning words, only a very few are removed. It's also worth noting that the OSPD is not the accepted word authority outside North America