Collins or the North American list

Updated September 4, 2026 · 2 min read

A word that was legal in one game gets rejected in another because different tables use different reference lists. The North American list (NWL) recognizes 107 two-letter words, while Collins (CSW) accepts 127. Choosing which list governs your table before play starts prevents these disagreements.

The short version

Agree on Collins or the North American list before the game begins.
Remember that no two-letter word contains the letter V in either list.
Play CH only when your table has agreed to use Collins.
Reject PH, which Collins removed in 2007 and North America does not include.

North America and Collins agree on a shared base of 107 two-letter entries. Common words like AN, AT, BE, BY, DO, GO, IF, IN, IS, IT, ME, MY, NO, OF, ON, OR, SO, TO, UP, US, and WE almost never start an argument. Other shared words often draw challenges at kitchen tables despite being valid in both lists: QI, ZA, XI, XU, JO, KA, OE, AE, EF, ET, AX, EX, OX, SH, HM, MM, OI, and UT.

These 20 words are the whole gap: 107 two-letter words in the North American list, 127 in Collins. No dictionary anywhere allows a two-letter word with V. C appears in exactly one two-letter word, CH, and only in Collins.

Collins contains 20 two-letter words that do not appear in the North American list at all. Those 20 words are CH, DI, EA, EE, FY, GU, IO, JA, KO, KY, NY, OB, OO, OU, ST, UG, UR, YU, ZE, and ZO. If your table follows the North American list, every one of these twenty words is invalid, even though a player may have used them under Collins rules elsewhere.

Letter restrictions follow from these lists. Neither dictionary permits any two-letter word containing the letter V. The letter C appears in exactly one two-letter word across both lists: CH, which is valid only in Collins. Additionally, Collins removed PH in 2007, so PH is not legal in either reference list today.

The mistake to avoid

The mistake is to assume a two-letter word legal in Collins is valid on a North American list. Words like CH, ZO, and JA are Collins only. Decide which list you are using before anyone begins placing tiles.

Questions that keep coming up

Is PH a legal two-letter word?

No, PH is not legal. Collins removed PH in 2007, and it is not in the North American list.

Are there any two-letter words that use the letter V?

No, there are no two-letter words containing a V in either Collins or the North American list.

How many two-letter words are legal in Collins compared to North America?

Collins has 127 legal two-letter words, which includes the 107 words from the North American list plus 20 additional words.