Heterogram

A heterogram is a word, phrase, or sentence in which each letter of the alphabet appears at most once. For example, the word "uncopyrightable" is a heterogram because it uses 15 distinct letters and no letter is repeated. Similarly, the phrase "jock nymphs quiz vats", while nonsensical, is a heterogram as it uses each letter of the alphabet exactly once. Longer heterograms can be challenging to construct.

The concept of a heterogram is distinct from a pangram, which is a phrase or sentence that contains every letter of the alphabet at least once. Thus, a pangram can be a heterogram if each letter appears only once, but not all pangrams are heterograms. The focus of a heterogram is on the unique presence of letters, rather than the complete inclusion of all letters.

Heterograms are a type of word puzzle and linguistic curiosity. Their construction often involves careful selection and arrangement of letters to avoid repetition. The word "subdermatoglyphic" is a notable example of a long heterogrammatic word, containing 17 unique letters. While some languages may have longer natural heterogrammatic words, constructed examples are more common for demonstrating the concept. The study of heterograms falls within the broader field of recreational linguistics.