Two 15-Letter Words With Zero Repeated Letters

In the world of wordplay, there's a special category of words called isograms (or heterograms) — words where no letter appears more than once. While most people know "uncopyrightable," there's actually a second 15-letter champion: "dermatoglyphics."

Uncopyrightable is the more famous of the two, meaning something that cannot be protected by copyright law. It's the word that shows up in trivia games and bar bets. But dermatoglyphics — the scientific study of fingerprints and skin ridge patterns — deserves equal recognition. Both words use exactly 15 different letters without repeating a single one.

The Alphabet Challenge

Think about how difficult this is: the English alphabet has 26 letters, and these words use 15 of them without repetition. That means each word is using more than half the alphabet, and every letter counts. One duplicate and the whole thing falls apart.

Other impressive isograms include:

• Ambidextrously (14 letters)
• Documentary (11 letters)
• Background (10 letters)
• Dialogues (9 letters)

But Wait, There's More

Word enthusiasts have gone even further. In 1990, linguist Edward R. Wolpow coined subdermatoglyphic — a 17-letter isogram meaning "of or relating to the area of skin directly below the fingerprint." While technically constructed for wordplay rather than scientific use, it demonstrates that even longer isograms are theoretically possible.

The word builds on "dermatoglyphics" by adding the prefix "sub-" (below) and the suffix "-ic" (relating to), creating what some consider the longest isogram in English. However, it hasn't entered standard dictionaries or common usage, leaving the 15-letter pair as the longest practical isograms.

Why This Matters

Beyond the novelty, isograms reveal something fascinating about language structure. They show the limits of how we can arrange letters without repetition while still creating meaningful words. It's harder than it sounds — try writing even a short sentence without repeating any letters. Go ahead, we'll wait.

For cryptographers and code-breakers, isograms have practical value too. They're useful in creating substitution ciphers where each letter maps to exactly one other letter. The longer the isogram, the more complex the cipher can be.

So next time someone claims "uncopyrightable" is the only 15-letter isogram, you can drop "dermatoglyphics" and watch their jaw hit the floor. Linguistic superiority: achieved.