10 longest words in English that will test your memory

Have you ever come across long English words that leave you tongue-tied? 

Think of the kind that makes you pause and take a moment or more to pronounce these words.  

With 171,476 words in the Oxford English Dictionary, we can’t help but wonder: what are the longest words in English?

Many of the longest words in the dictionary refer to medicine or chemistry. 

Some of the longest English words are so long that they are not included in dictionaries.

The longest word in English, “Methionylthreonylthreonylglutaminylarginyl…isoleucine”, is the chemical name for the largest protein found in humans. 

It has a staggering 189,819 letters and has not been included in the English dictionary as it would take up over 50 pages.

Due to its length, some have argued that it is not even a word. 

Longest one-syllable word in English

When it comes to the longest one-syllable word in English, these words are surprisingly long for one-syllable words. 

One example is “screeched,” a verb meaning “made a loud, squealing noise.” Here are some other long one-syllable words: 

• Scratched
• Scrunched
• Stretched
• Straights
• Strengths

Longest English words without vowels

If you’re wondering about the longest English word without vowels, here are some examples:

• Twyndyllyngs: A word of Welsh origin, meaning twins
• Symphysy: A fusion of two bodies or parts
• Rhythms: Repeated patterns of sounds

The longest word in English refers to a medical condition commonly known as “black lung.” Source: AFP

10 longest words in English that will test your memory

1. Pneumonoultramicroscopicsilicovolcanoconiosis

This word is known for being one of the world’s longest words in English. This 45-letter word refers to a lung disease that is caused by the inhalation of silica or quartz dust. 

It was coined in 1935 by the then-president of the National Puzzlers’ League, Everett M. Smith. 

While the word is made up, the disease is real and it’s known under the names pneumoconiosis, silicosis, or black lung.

It can be broken down into: 

• Pneumono: from ancient Greek, which means lungs
• ultra: from Latin, meaning beyond
• micro and scopic: from ancient Greek, meaning small looking, referring to the fineness of particulates
• silico-: from Latin, silicon
• volcano: from Latin, referring to volcano
• coni: from ancient Greek, which means dust
• -osis: from ancient Greek, suffix to indicate a medical condition

2. Hippopotomonstrosesquippedaliophobia

At 36 letters, hippopotomonstrosesquippedaliophobia is the second longest word in English. The irony is that it is one of the longest words in English and refers to the phobia or fear of long words. 

Since the word is so long and may scare a few, many have coined a simpler term known as sesquipedalophobia. 

However, this fear isn’t actually recognised by the American Psychiatric Association. It is considered to be a social phobia. In the US, specific phobias, such as the fear of long words, affect between 3 to 15% of the population. 

The word can be broken down into:

• Sesqui derives from Latin and refers to one and a half, and the phrase “sesquipedalia verba” was used long ago by the Roman poet Horace to criticise writers who used the words “a foot and a half long”
• Hippopotamine refers to “something very large” 
• The word “monstr” is the Latin origin of a ‘monstrous being’ or something that is huge or terrifying

Supercalifragilisticexpialidocious became popular because of the film Mary Poppins. Source: AFP

3. Supercalifragilisticexpialidocious

Coming in third on the list of longest words in English is supercalifragilisticexpialidocious. 

At 34 letters, this word became popular from the 1964 musical film “Mary Poppins.” This mouthful of nonsensical syllables has brought cheer to audiences for many years. 

In the film, it is described as the word to use ” when you have nothing to say.” According to the Oxford English Dictionary, the word has now come to mean an expression of excitement or ” wonderful.” 

It can also be commonly used as a shortened adjective, supercalifragilistic or as an adverb supercalifragilistically. 

Many dictionaries have since recognised it, but not all. 

The word is made up of the following root words:

• Super: above
• Cali: beauty
• Fragilistic: delicate
• Expiali: to atone
• Docious: educable

4. Pseudopseudohypoparathyroidism

Pseudopseudohypoparathyroidism is a medical term that refers to a relatively mild form of pseudohypoparathyroidism. 

This 30-letter word is the only word in the dictionary with a repetition of the word pseudo. It was named for its similarity to pseudohypoparathyroidism.

5. Floccinaucinihilipilification

Floccinaucinihilipilification is the act of regarding something as unimportant or as worthless. It is commonly used in a humorous way.

Ironically, floccinaucinihilipilification is a pretty valueless word itself; it’s almost never used except as an example of a long word.

This 29-letter word consists of a series of Latin words (flocci, nauci, nihili, and pili), all signifying “at a small price” or “for nothing,”

The first recorded use is by William Shenstone in a letter in 1741: “I loved him for nothing so much as his flocci-nauci-nihili-pili-fication of money”.

6. Antidisestablishmentarianism

The word antidisestablishmentarianism, with 28 letters and 12 syllables, is one of the longest words in English.

It originated in 19th-century Britain when a political movement sought to separate church and state. The opposition wanted to disestablish the Church of England in Ireland, Scotland and Wales.

The original meaning of the word was applied to those who supported this movement. Today, the word is rarely used but means to be against the establishment of any state religion.

One of the longest words in English comes from William Shakespeare’s works. Source: AFP

7. Honorificabilitudinitatibus

At 27 letters, it is the longest word in the English language that alternates between consonants and vowels.

Deriving from Latin, it means honourable, honourableness or “the state of being able to achieve honours.”

This word has only appeared once, appearing in Shakespeare’s works. It was used mockingly in Love’s Labour’s Lost to insult people who like to use big words.

8. Thyroparathyroidectomized

Thyroparathyroidectomized is another medical term on this list. It is one of the longest words in English, with 25 letters.

This medical term refers to the surgical removal of both the thyroid and parathyroid glands.

One of the longest words in English was invented while looking for gas to be used as a refrigerant. Source: AFP

9. Dichlorodifluoromethane

This 23-letter-long word came about as three companies in the US were searching for a nonflammable, nontoxic alternative to ammonia and sulfur dioxide to use as a refrigerant.

In the 1920s, a researcher Thomas Midgley discovered a colourless gas now known as dichlorodifluoromethane.

10. Incomprehensibilities

At 21 letters long, incomprehensibilities is the tenth longest word in English. In the 1990s, it set the record as the longest word “in common usage” – which seems almost incomprehensible.

It refers to the state of being impossible or extremely difficult to understand and comes from the Latin word “incomprehensibilis.”

Here’s how you can use incomprehensibilities in a sentence: The incomprehensibilities of my friends are beyond me.