13-letter words

A 13-letter word needs six letters already on the board before a seven-tile rack can play it, so this length belongs to crosswords and vocabulary builders. INTERNATIONAL, UNDERSTANDING and INVESTIGATION lead 322 common words. The spelling split between -IZATION and -ISATION is the quirk worth learning.

13-letter words at a glance

• 14,695 words have exactly 13 letters in at least one of ENABLE, Collins or NWL2023.
• P opens 1,597, then C with 1,487 and S with 1,477, a three-way race decided by 120 words.
• 7,018 words end in S, just under half of the list.
• RAZZAMATAZZES scores 51 points, and the average 13-letter word scores 20.4.
• Only 322 are common words; the other 14,373 are rarer.
• 155 words end in -IZATION and 150 in -ISATION, so the spelling you choose changes your odds.

Why does P open more 13-letter words than S?

Prefixes tip it. PRE opens 254 words and PRO 205, together 459 of P's 1,597, about 29%.

C keeps pace through CON, which opens 350 words, and COM adds 129. S trails C by only 10 words.

The second letter is E in 2,456 words, about one in six, then O (1,953) and N (1,740). I, A and R sit within seven words of each other at 1,306, 1,300 and 1,299.

At the thin end, Y begins 10 words, X 20, J 36 and K 51. Q begins 86.

How the dictionaries split on -IZATION and -ISATION

155 words end in -IZATION and 150 in -ISATION, almost a dead heat. Collins accepts 146 of the first group and 148 of the second.

NWL2023 is lopsided: it accepts 119 -IZATION words but only 36 -ISATION words. ENABLE takes just 5 of the -ISATION group, among them MODERNISATION; PRIVATISATION and GLOBALISATION appear in NWL2023 and Collins only.

Of the 150 -ISATION words, 114 are missing from NWL2023, so an American-rules game punishes the British spelling.

So the safest spelling in every list is the Z: MODERNIZATION is valid in all three dictionaries and scores 25 to the S version's 16.

Which endings dominate 13-letter words?

• S closes 7,018 words, including plurals like OPPORTUNITIES and ORGANIZATIONS.
• -IONS ends 690, and 553 of those are -ATIONS.
• -ITIES ends 317, against 346 for singular -ITY, a gap of 29.
• -ICALLY ends 232 adverbs, for example AUTOMATICALLY. -NESS ends 609, among them 103 -OUSNESS words.
• -ISTS ends 278, slightly more than the 275 that end in -IST.
• -ABILITY ends 157 words and -IBILITY 42; VULNERABILITY and COMPATIBILITY show each.

Prefix families that build 13-letter words

UN opens 624 words and RE 602, a gap of 22, with NON adding 266. UNCONDITIONAL, UNCOMFORTABLE and UNPRECEDENTED cover the everyday UN side.

Technical prefixes form smaller families. ANTI opens 132 words, COUNTER 80, MICRO 79, MULTI 72 and PSYCH 49. MULTINATIONAL, ANTIBACTERIAL and COUNTERATTACK show the pattern.

Mid-sized families include DIS (306), PRE (254), OVER (223), PRO (205) and MIS (133). The common word disappearance is simply DIS plus the ten-letter stem APPEARANCE, a pattern you can test on any clue with a prefix-sized gap.

INTER opens 201 words, such as INTERPERSONAL and INTERVENTIONS. Fit the prefix first and the remaining ten letters become a far shorter search.

Which 13-letter words are most common?

INTERNATIONAL, UNDERSTANDING, INVESTIGATION and ENVIRONMENTAL rank first by frequency. Adverbs follow: APPROXIMATELY, UNFORTUNATELY and SIGNIFICANTLY.

Only 78 of the 322 common words end in S, about one in four, against nearly half across the whole list. Conversational words are mostly singular, so a clue that sounds like speech points away from the S ending.

Adverbs are a big family too. 918 words end in -LY, and 232 of those, about a quarter, end in -ICALLY. 320 of the 322 common words carry a dictionary definition, so you can check the meaning of nearly any of them.

Six of the first 30 common words end in -TION: investigation, communication, participation, collaboration, consideration and concentration. That one ending carries a fifth of the top 30.

Scrabble scores for 13-letter words

RAZZAMATAZZES scores 51, and no other 13-letter word in the three dictionaries reaches 50. Only 2 words hit 40 and 355 reach 30. Collins-only CHIQUICHIQUIS scores 41.

Behind that, EMBEZZLEMENTS reaches 37 in all three dictionaries. Common words stay lower: CHARACTERIZED scores 30 and APPROXIMATELY 29.

RAZZAMATAZZES is the 11-letter RAZZAMATAZZ plus ES. Its four Z tiles are worth 10 points each, which is 40 of the 51.

Rare letters carry the totals. Z sits in 956 words, X in 503, Q in 296 and J in 132. OVERQUALIFIED reaches 29 on the strength of a single Q.

Count the board letters before you commit. A 13-letter play uses at most seven of your tiles, so six must already be there.

How much do the three dictionaries agree?

All three agree on 7,736 words, just over half of the 14,695. Collins carries 13,857, NWL2023 carries 9,323 and ENABLE carries 7,827.

Collins alone supplies 5,319, more than a third of the list.

Playing ENABLE or NWL2023? Then 838 words are valid in those lists but not in Collins. Within that group, 38 sit in both lists at once.

ENABLE also lists 42 words that neither Collins nor NWL2023 accepts. Those are the ones a phone-app opponent may play and a club referee would reject.

A caution about 13-letter words