British vs American Word Lists

British and American Scrabble use different word lists — historically, Collins Scrabble Words (CSW, international) and the NASPA Word List (NWL, North America). CSW is the larger list and has always been more inclusive of British-English spellings. NWL has grown over successive editions and now includes many spelling variants it once excluded.

This guide covers the current lists in use, the categories of spelling differences between British and American English, and which list you should learn depending on where you play. For any specific word, always confirm with an official word finder for the exact list edition your event uses — the two lists are updated on different cycles, and this article does not track every edit.

The three main lists

CSW is the larger list — every long-standing NWL entry is either in CSW already or on the CSW committee's radar. Words that are exclusive to CSW are largely British-English spellings, dialect words, and short two- and three-letter words that NWL has been slower to add.

British / American spelling categories

Words that end in the following patterns tend to be the ones that trip cross-Atlantic players up. Whether an individual variant is legal in NWL2023 or CSW24 depends on the current edition of that list — check with your official word finder rather than relying on the general pattern below.

Both COLOUR and COLOR are valid in the current major tournament lists — the older assumption that COLOUR was CSW-only no longer holds. Whenever a specific spelling matters for a play or a challenge, confirm it against the current edition of your event's list rather than relying on the -OUR/-OR rule of thumb.

Which list should you learn?

• Playing casual Scrabble in North America → learn NWL (NWL2023 is the current edition).
• Playing casual Scrabble in the UK, Europe, Australia, South Africa or India → learn CSW (CSW24 is the current edition).
• Playing Words With Friends → Zynga maintains its own proprietary accepted-word list. It is not a superset of NWL: the two lists overlap heavily but each contains entries the other rejects, so always confirm a specific word against the game itself.
• Using an unscrambler for anagram puzzles or Wordscapes → ENABLE (like WordUnscramble.uk) matches most of what those apps accept.

Notable CSW entries worth memorising

If you're a NWL player crossing into international play, these short high-frequency, high-value CSW entries are the ones that most often earn back their memorisation cost. Confirm each against the current NWL edition — some of these have been added over time.

Regional word lists beyond English

French uses ODS (l'Officiel du Scrabble). German uses the Scrabble-Turnierliste (STL). Both are as strictly maintained as NWL and CSW, and tournament players use them exclusively for their languages.

Why the lists diverge at all

Historical accident. The North American list descends from Merriam-Webster's American dictionaries; CSW was created by merging the North American list with the Chambers Dictionary — a British reference known for its liberal inclusion of dialect words. There have been repeated attempts to unify the lists; commercial and cultural factors have blocked them so far.