SOWPODS is the word list used in English-language tournament Scrabble in most countries except the USA, Thailand and Canada. The term SOWPODS is an anagram of the two acronyms OSPD and OSW, these being the original two official dictionaries used in various parts of the world at the time. Although the two source dictionaries have now changed their respective titles the term SOWPODS is still used by tournament players to refer to the combination of the two sources. There has not been any actual hard-copy list produced called SOWPODS, although the current Collins Scrabble Words, or CSW, is in effect the full SOWPODS list by a different name.
Currently the two main sources for the words making up the combined list known as SOWPODS are:
In 1980 in the United Kingdom, the Chambers Dictionary replaced the Shorter Oxford Dictionary as the official choice for arbitration of the British National Scrabble Championship. In 1988 for the first time a single list of all the valid words, without the ambiguity of discussing conjugations, declensions and plurals was published under the title Official Scrabble Words from Chambers (this would come to be known as OSW). North American Scrabble was using the OSPD, hence when the first World Scrabble Championship took place in 1991 words from either word source were allowed.
Over the following years there was disagreement in the competitive Scrabble community over the desirability of a combined word source, which came to be known as SOWPODS as an easily pronounced anagram of OSW and OSPD. Australia changed all its rated tournaments to using the SOWPODS word list in 1994, while the UK made the same change in 2001. This latter move coincided with the publication of the first official book to contain all words from OSW and OSPD (Chambers' Official Scrabble Words: International Edition).