Ask which English word is the longest and you will get several different answers, all defended with confidence. That is because the question hides another one: what do we mean by a word, and by length?
This article covers the main candidates, from a chemical name with well over 180,000 letters to a 28-letter word that people actually use. You will also see why each one wins in its own category, and how to pick the answer that fits your purpose.
Why there is no single answer
The first thing to know is that the answer depends on how you define a word. Reference material on the topic consistently makes this point. The result changes depending on whether you allow technical terms, place names, coined forms, and strings that exist only as written letters.
Some useful questions to ask before choosing a winner:
- Must the word appear in a major dictionary?
- Are scientific and technical names allowed?
- Does a word coined mainly to be long count?
- Does anyone actually use the word in earnest?
Each question narrows or widens the field. Below are the best-known contenders, from longest to shortest.
The longest of all: the chemical name of titin
If you allow any technical term at all, the winner is the chemical name of titin, a protein. It is reported to run to 189,819 letters. Other accounts say simply that it is over 180,000 letters long.
It is often described as the longest known word overall. But its status as a word is disputed. It is a systematic name, built mechanically from the structure of the molecule rather than a term that people say or write in ordinary language. Whether such a name should count as a word is exactly the kind of definitional choice that splits the debate.
The longest in a major dictionary
Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters)
This is the word most often given as the answer. At 45 letters, it is described as the longest English word to appear in a major dictionary. It names a lung disease, and its length comes from stringing together technical parts.
There is a catch. Sources note that it was coined to be long and is rarely used in earnest. It earns its place in dictionaries and trivia, but few doctors or writers reach for it in daily work. Recent coverage still calls it a leading candidate for the longest English word, while stressing that the answer depends on what counts as a word.
Dichlorodiphenyltrichloroethane
Dictionaries differ. The longest word listed in Collins English Dictionary is dichlorodiphenyltrichloroethane, the full chemical name of DDT. It is a real technical term, not a stunt word, which makes it a different kind of winner from the 45-letter lung disease.
The comparison shows why the phrase a major dictionary is not as simple as it sounds. Different dictionaries include different entries, so the longest entry varies from one to the next.
The longest word not coined just to be long
Pseudopseudohypoparathyroidism (30 letters)
If you want to exclude words invented as a record attempt, this 30-letter medical term is a strong choice. It is described as the longest word that was not coined solely to be the longest. It is a term from medicine, and its length comes from stacking prefixes onto a condition name.
It sits in a middle category: technical, but not created as a stunt.
The longest non-technical coined word
Floccinaucinihilipilification (29 letters)
For everyday vocabulary rather than science, the 29-letter floccinaucinihilipilification is the standout. Oxford Dictionaries describes it as the longest non-technical coined word. It refers to the habit of estimating something as worthless.
It is a deliberate construction and an unusual one, but it is not a chemical or medical term. That makes it a favorite among people who want a long word that belongs to ordinary language.
The longest word people really use
Antidisestablishmentarianism (28 letters)
The 28-letter antidisestablishmentarianism is the best answer if you want a long word that grew naturally and follows normal rules of word-building. Oxford Dictionaries describes it as the longest non-coined, non-systematic English word. Coverage of it presents it as a genuine long word, in contrast with words made up as stunts.
That is a lot of qualifiers, but they are the point. It is neither a chemical name built by formula nor a word invented for a contest. It is simply a long word that entered the language.
Quick comparison
- Longest overall: the chemical name of titin, reported at 189,819 letters, though its status as a word is disputed.
- Longest in a major dictionary: pneumonoultramicroscopicsilicovolcanoconiosis, 45 letters.
- Longest in Collins English Dictionary: dichlorodiphenyltrichloroethane, the full name of DDT.
- Longest not coined solely to be longest: pseudopseudohypoparathyroidism, 30 letters.
- Longest non-technical coined word in Oxford Dictionaries: floccinaucinihilipilification, 29 letters.
- Longest non-coined, non-systematic word in Oxford Dictionaries: antidisestablishmentarianism, 28 letters.
How to choose the right answer
The right word depends on why you are asking. A few practical guidelines:
- For a quiz or trivia answer, give pneumonoultramicroscopicsilicovolcanoconiosis, and mention that it has 45 letters and appears in a major dictionary.
- For a pure record, name the chemical name of titin, and add that its status as a word is disputed.
- For a word people really use, choose antidisestablishmentarianism.
- For a word from ordinary language that was deliberately built, choose floccinaucinihilipilification.
When you write or speak about this, state your criteria. A sentence such as the longest word in a major dictionary is clearer and more accurate than the longest word in English.
Conclusion
There is no undisputed longest word in English. The chemical name of titin is by far the longest string, at roughly 190,000 letters, but many people do not accept it as a word. Among words found in a major dictionary, the 45-letter pneumonoultramicroscopicsilicovolcanoconiosis is the usual answer.
If you care about words with a more natural history, the 30-letter pseudopseudohypoparathyroidism, the 29-letter floccinaucinihilipilification and the 28-letter antidisestablishmentarianism each win a narrower category. The most honest answer is to name the definition first, then the word.
