Currently, in North America, the definitive reference for which words are valid in tournament play is the NASPA Word List, which in 2019 replaced the Official Tournament and Club Word List. However, internationally, the definitive reference is Collins Official SCRABBLE™ Words. The main practical difference between the two lists is that the latter contains more words.

It occurred to me, though, that these two word lists are periodically updated, and the exact dates of the updates do not always coincide. Therefore, it is conceivable that, even though the international list is supposed to contain everything in the North American list and more, the two lists could briefly get "out of sync," resulting in some words being valid in North America but not valid internationally, at least for a short period of time. This could happen either because some word is added to the North American list before it gets added to the international list, or a word is deleted from the international list before it is deleted from the North American list.

Has this ever happened?

1 Answer 1


Yes, the NASPA Word List (NWL) and Collins Official Scrabble Words (CSW) do get out of sync.

In fact they are currently out of sync, with the NWL2020 containing 2417 words that are not included in CSW21, of which there are 52 under 9 letters in length.

Primarily this discrepancy is caused by Collins selectively excluding more words deemed to be hate speech than NASPA does (they both exclude some, Collins is just more strict due to the additional regions covered). There are also a few trademarked works Collins doesn't include as they would be tricky to use in a printed edition.

Helpfully NASPA has a list of the 2-8 letter words included in their Collins Cheat Sheet

  • 1
    Thanks for this answer. I saw a recent Slate article which says that the latest revision of NWL (NWL2023) contains words such as HORSEFEATHERSES and ROUXES and FECESES, which seem to be the result of misapplying certain "rules" of word formation. I wonder if Collins will add these dubious "words" in their next revision. Nov 30, 2023 at 13:35

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