10 Longest Words in the English Language

10 Longest Words in the English Language

Last Updated: Dec 30, 2019
How many words exactly are in the English language? The second edition of the current 20-volume Oxford English Dictionary contains 171,476 words in current use. That’s a lot! Which gets the mind thinking the next question, what’s the longest word in current use today?

Many of the longest words in the dictionary refer to medicine or chemistry. You’ll find a few defined in here along with other long words that you may or may not already use. Here’s how Merriam-Webster defines the ten longest words in the English language.

1. Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters)

Pneumoconiosis caused by inhalation of very fine silicate or quartz dust.

2. Hippopotomonstrosesquippedaliophobia (36 letters)

Ironically, Hippopotomonstrosesquippedaliophobia is one of the longest work in the dictionary and is the name for a fear of long words! Who would have thought, right?

3. Supercalifragilisticexpialidocious (34 letters)

Perhaps the best word of all! Made popular by the film Mary Poppins, Supercalifragilisticexpialidocious is something to say when you have nothing to say.

4. Pseudopseudohypoparathyroidism (30 letters)

A relatively mild form of pseudohypoparathyroidism that is characterized by normal levels of calcium and phosphorus in the blood.

5. Floccinaucinihilipilification (29 letters)

The longest unchallenged nontechnical word that not all directories recognize, that including Merriam-Webster. According to alternative sources, floccinaucinihilipilification is the act or habit of describing or regarding something as unimportant, of having no value or being worthless. Often times, it is used in a humorous way.

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6. Antidisestablishmentarianism (28 letters)

A term referring to a political movement in 19th century Britain that sought to separate church and state. In this case, political movement wanted to disestablish the Church of England as the official state church of England, Ireland and Wales.

7. Honorificabilitudinitatibus (27 letters)

The longest word in Shakespeare’s works. Honorificabilitudinitatibus is the longest word in the English language featuring alternating consonants and vowels.

8. Thyroparathyroidectomized (25 letters)

A medical term that defines the excision of both the thyroid and parathyroid glands.

9. Dichlorodifluoromethane (23 letters)

A chlorofluoromethane CF2Cl2.

10. Incomprehensibilities (21 letters)

Impossible to comprehend. In the 1990’s, incomprehensibilities set the record as the longest word “in common usage.”

LONGEST ENGLISH WORD:Methionylthreonylthreonylglutaminylarginyl…isoleucine (189,819 letters)

If we’re talking chemistry, the longest chemical name is 189,819 letters long. It is the chemical name for titin, a giant filamentous protein essential to the structure, development, and elasticity of muscle. As to whether or not this is an actual word is disputed by many. It is not in the Merriam-Webster dictionary, so you shouldn’t ever have to worry about spelling it. ?

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Comments

  • Susan R Stephenson
    Reply

    Thank you all. That was fun and I like knowing there are so many of us logophiles “word nerds” or sesquipedalianophiles (someone one who loves long words – I think I made this up – sort of) out there :)

  • AlwaysThinkPositive
    Reply

    Anti-counterrevolutionaries

  • Some Other Words
    Reply

    radioimmunoelectrophoresis (26), u need defenition so it means: radiommunoelectrophoresis in which the substances separated in the electrophoretic system are identified by radioactive labels on antigens or antibodies.
    psychoneuroendocrinological (27) means: it is the clinical study of hormone fluctuations and their relationship to human behavior. It may be viewed from the perspective of psychiatry, where in certain mood disorders, there are associated neuroendocrine or hormonal changes affecting the brain.
    quinquagintaquadringentilliard (30) it’s some really high number

    • Evan

      Skewes number might be an even larger number because it is equal to 10 to the
      10th power to the10th power to the 34th power.

  • hi
    Reply

    you forgot greatgreatgreatgreatgreatgreatgrandfather lol

  • Karishannaliyamiyesariasheleya
    Reply

    ‘Karishannaliyamiyesariasheleya’is my name 😊

  • Anonymous
    Reply

    That’s nice 😊

  • Jagged Peak
    Reply

    Methanidylidynesilanylium has 25 letters and is the chemical compound of silicon and carbon, a.k.a. silicon carbide!

    • zawwar Mehboob

      Perhydrocyclopentanophenanthrene its even longer its a cholesterol compound.

  • olivia
    Reply

    why would anyone make a 189,891 letters long word

  • Alek Sander
    Reply

    The longest words belong to Science!

  • nonanonacontanonactanonalia
    Reply

    nonanonacontanonactanonaliagon is longest name for a polygon

    • hehe

      Rhombicosidodecahedron is one of my favorites

    • Alek Sander

      Nonanonacontanonactanonaliagon is a 9,999-sided polygon.

  • Cole the 10 year old
    Reply

    what about precipitevolissimevolmente
    which is a 26-letter-long adverb.

  • sksk
    Reply

    ummmm another word with 27 letters is ethylenediaminetetraacetate that you forgot

  • Christopher Nowak BFA MLIS
    Reply

    Deinstitutionalisation and Counterrevolutionaries??!!

    • rhonda

      what about rhombicosidodecahedron

  • Kyliah Williams
    Reply

    This Website Is Pretty Cool! 😎

    • Zie

      These words are making me Supercalifragilisticexpialidocious🤣🤣🤣🙌

  • yup meeeeeeeeeeee Pneumonoultramicroscopicsilicovolcanoconiosis
    Reply

    tetrahydrocannabinol (20 letters): tetrahydrocannabinol stands for psychoactive substance present in marijuana.

  • yup meeeeeeeeeeee Pneumonoultramicroscopicsilicovolcanoconiosis
    Reply

    forget hyperbetalipoproteinemia (24 letters): hyperbetalipoproteinemia stands for a genetic disorder characterized by high levels of beta-lipoproteins and cholesterol.

  • THE LEGEND
    Reply

    Longest place name = llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch

    • yup meeeeeeeeeeee Pneumonoultramicroscopicsilicovolcanoconiosis

      Nope, Taumatawhakatangi­hangakoauauotamatea­turipukakapikimaunga­horonukupokaiwhen­uakitanatahu, New Zealand
      The world’s longest place name belongs to a hill near Porangahau in the southern Hawke’s Bay in New Zealand. It is a name given in the Maori language. This hill is 305 meters tall and is famously known for its long name. This name has since been shortened to Taumata for the ease of pronunciation. The meaning of the name has been translated to mean “the place where Tamatea, the man who had big knees, the climber of mountains, the slider, the land-swallower that traveled about, played the nose flute that he had to the loved ones.” With 85 characters, it is the longest place name in the world according to the Guinness World Records.

  • Lily
    Reply

    I just LOVE this website.

    • Alek Sander

      This website loves you too!

    • Matt

      Paramethoxymethaphetamine has 25 letters. Forgot about it.

    • ….

      wow im late on the website

  • Bryan Phillips
    Reply

    Methylphenidate or in shampoo methylisothiazolinone and methylisothiazide tributyline is a fat compound methyltertiarybutylether methylbutyltertiaryether and ethyltertiarybutylether in gasoline were damaging engines especially small engines and are no longer used. I used to be a mechanic

    • Jaz

      And Methylchloroisothiazolinone, mah dude 😎

  • Hippopotamus
    Reply

    What about kakorrhaphiophobia? Fear of failure

    • Turtle

      Isn’t that just being normal

  • Emmanuel
    Reply

    The word “Tmesis” is more incredible than long words.

  • Vinoth
    Reply

    Tamil language has 247 letters

    • Gabriella

      Wow I can’t believe this

  • Bradley Ross
    Reply

    Antidisestablishmentarianism actually has the definition for disestablishmentarianism. The attached sound clip has the definition correct. What is also interesting is that antidisestablishmentarianism is recognized by my spell checker but disestablishmentarianism is not.

    • George

      Agreed – anti-definition. What about AntidisestablishmentarianismIST!

  • someone
    Reply

    transdifferentiation

    • Gerry jones

      I love long words. I wish all words were longer.

  • idefkwtf
    Reply

    Just imagine you having to be a doctor and telling the patients you have Methionylthreonylthreonylglutaminylarginyl…isoleucine for 3 hours and they are already dead and you keep going on and on, even at the freaking funeral!

    • lololol

      Teacher: ok kids, how do you spell Methionylthreonylthreonylglutaminylarginyl…isoleucine?

      Kids: O_O

  • 🐲🦄😇😸
    Reply

    Hippopotomonstrosesquippedaliophobia means fear of long words and is a long word!!

  • Robo
    Reply

    Amazing!!

  • ^_^
    Reply

    Please add this word and put it on the 12th place (19 letters)
    Chlorofluorocarbons
    and put this on the 11th place (24 letters)
    hydrochlorofluorocarbons

    • ^_^

      I meant put hydrochlorofluorocarbons on the 9th place

    • Hippopotamus

      Electroencephalographically

    • -_-

      thought chlorofluorocarbons isn’t counted as a long word

  • James Mangong Ngor Ajang
    Reply

    I have never ever come accross such English words.It’s a great surprise.

  • scottish.cow
    Reply

    what about polyetherketoneetherketoneketone

  • Leah
    Reply

    Some people have Hippopotomonstrosesquipedaliophobia and then there’s me who has Hippopotomonstrosesquipedaliophilia!!

  • Zainab
    Reply

    I am only 9 years old and I know the words pneumonoultramicroscopicsilicovolcanoconiosis

    • Abi

      Cool

  • Unknown
    Reply

    this is Supercalifragilisticexpialidocious

  • Oh yeah yeah
    Reply

    I learned a new word to flex with :] Pneumonoultramicroscopicsilicovolcanoconiosis

  • Rather not say
    Reply

    I knew the first three and can pronounce the first but really no. 2, ironic how are the sufferers meant to say their condition

    • kay

      facts

  • No
    Reply

    29 letters Methyl​enedioxy​methamphetamine,

  • Tsehesenestsestotse
    Reply

    You missed spectophotofluorometrically, but I don’t know the definition

    • Alek Sander

      A spectrophotofluorometre is a tool for assessing the amount of light given off by something, so in its 28-letter adverbial form, we could use a sentence like “the sample was assessed spectrophotofluorometrically.”

  • B r U h
    Reply

    The fear of long words’ name is ironic

    • Alek Sander

      Aaaaaaaaaaaaaaaaaaaaaaahhhhhh!!!!!!

    • Hippopotamus

      What about electroencephalographically

      • Alek Sander

        Sure – Electroencephalograph in it’s adverbial form would be electroencephalographically (27 letters).

  • Lemony Snicket lover56
    Reply

    Some of these words are confusing to spell I can’t even remember them all!!!
    I like pronouncing them though.

    • Lemon Zest ( O-O )

      Me too! They are fun to pronounce

  • not going to say my name
    Reply

    you missed out a word which is 24 letters long: Lymphangioleiomyomatosis (it’s a disease of the lungs)

  • Unknown
    Reply

    What about antimonopologeographicationalism

  • yeet
    Reply

    I watched the whole video of the longest word, a great waste of a hour.

    • Alek Sander

      I watched it twice just to make sure. You’re right.

  • Iorwuese Lubem Amos
    Reply

    I never even knew that this kind of words exist self i try to check on Google today to see and to my greatest amazement i found it na so things they this world unless you research and see by yourself….

  • Mikaela
    Reply

    Super long words!

    • Adriana

      Yep!

    • Johm M Sims

      Somewhere in the middle belongs a word I learned today in nursing school …..Esophagogastroduodenoscopy….26 letters

  • Shahryar
    Reply

    I offer this 20 word for number 11:
    Compartmentalization

  • Jayden
    Reply

    I forgot what it’s called but the fear of the number 666 is a long word

    • Alek Sander

      Hexakosioihexekontahexaphobia

    • Jessica Khumalo

      I was astonished to by the compartmentisation , but guess the ones introverted are homogeneous to science but slightly heterogeneous ..

  • Fireproofsquirrel
    Reply

    What about antidisestablishmentarianism?

    • Alek Sander

      Yup, it’s listed at #6 in the post.

  • # yourcommentreader..
    Reply

    This website comments just made my day 😆

    • Jennifer

      lol

    • Kay

      Lol along with Jennifer

  • Bee
    Reply

    Common usage? – ‘compartmentalisation’, 20 letters- read in a few papers today and thought ‘that’s a long word’ and so here I am.

    • Trisha

      I was bored and I googled a word and here I am. Someone posted the longest girls name is next. Lmao

  • Chris
    Reply

    Yesterday dust entered my lungs and this site helped me coz now I know that the disease I have is pneumonoultramicroscopicsilicovolcanoconiosis

    • COWS ARE COOL

      how about friggatriskaidekaphobia? It’s the fear of Friday the 13th.

  • Unicorn 🦄
    Reply

    I love the longest one! 😂

  • Divyesh
    Reply

    What is the longest word ever?!

    • Alek Sander

      You won’t find it in the dictionary, but this English word has 189,819 letters (Methionylthreonylthreonylglutaminylarginyl…isoleucine). There’s a video posted above just in case you want to know how to pronounce it.

    • Umesh Kumar Chaudhary

      Great

  • LifeLang 09
    Reply

    The last word has lots of “Y”s.

  • Jane Gwyneth Caballa
    Reply

    notice they didnt put DDT-
    Dichlorodiphenyltrichloroethane(31)

  • steven
    Reply

    who created the last word from the list it was too long for me so when I watched it I didn’t even watch 1minute then I just closed my MacBook Pro.😂

    • James

      Lol

  • steven
    Reply

    Some videos say subscribe even if it’s just telling long words a
    few times.😂

  • Steven
    Reply

    wow so long words I think that I am having a fear of long words😀

    • Alek Sander

      😂

  • Beata Wasil
    Reply

    Doctor: You have got the fear of long words.
    Man: What is the proper name for that?
    Doctor: Its called Hippopotomonstrosesquippedaliophobia.
    Man: *Screams and runs away*

    • Alek Sander

      😂

    • Calskee

      Hilarious!

  • Super Cat
    Reply

    Thanks iris for helping me with my assignment today. Thanks to you I feel Supercalifragilisticexpialidocious!!!!!!!🙏🏻😁😻🥰❤️❤️

  • Super Cat
    Reply

    At my school I have 3 Mary Poppins fans. All the time they say Supercalifragilisticexpialidocious and I never knew what that meant, but now I know thanks to this app. And I think its a funny 😄 word to say. 😁😁

  • Scriptingtalez script
    Reply

    I memorize 3 the Supercalifragilisticexpialidocious, Hippopotomstrosesquippedaliaphobia, and Pneumonoultramicroscopicsilicovolcanoconiois

    • Pneumonoultramicroscopicsilicovolcanoconiosis

      still didnt spell the last one right.

  • Meee
    Reply

    Rhombicosidodecahedron is a poloygon and it is 22 letters

  • Muhesi Joab
    Reply

    So many but not easy to pronounce

  • Sheryl Limon
    Reply

  • Lukas
    Reply

    for all you people who like words that nobody knows, zyzzyva (a type of tropical weevil) is the last alphabetical word.

    • Lukas

      also i advise that you guys add hepaticocholangiogastrostomy.

    • Lukas

      it has 28 it ties for 6th place

  • PewDiePie
    Reply

    Soooooooo long words! I think I am going to get hippopotomonstrosesquippedaliophobia!!!

    • Alek Sander

      Lol… Best comment so far!

  • Falguni Sharma
    Reply

    This was mind boggling stuff I’ve come across in a long time. Keep on penning down such blogs often.

    • Laura Grugle

      The biggest word than I’ve ever known was Pneumonoultramicroscopicsilicovolcanoconiosis

  • 100123
    Reply

    Cooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooool.

  • Tshepo Rasello
    Reply

    those are some long words but it only took me a few minutes to learn pneumonoultramicroscopicsilicovolcanoconiosis

  • JJM
    Reply

    Whatever happened to “semiphotospectroheliographically”

  • Lina Fei
    Reply

    How about Tetaumatawhakatangihangakoauaotamateaurehaearuripukapihimaungahoronukupokaiwhenuaakitanarahu

    • Alek Sander

      I can’t find any information that this is a real word. Source please.

    • hi

      it is the name of a hill in New Zealand.

  • soo· pr· ka· luh· fra· juh· li· stuhk· ek· spee· a· luh· dow· shuhs
    Reply

    How did Supercalifragilisticexpialidocious become a real word in the dictionary from a show? And yes I am too lazy to search it my self. Also, the girl with the longest name try and beat that.

    • Ofre Timothy otiede

      Which one is the shortest in the dictionary

    • Hippopotamus

      The shortest word without vowels is Cwtch, but the shortest word with vowels is euouae. But basically, A and I are the shortest words ever

    • stephanie

      what does supercalifragilisticexpialidocious mean

      • Alek Sander

        Use your imagination. Walt Disney encouraged imagination.

    • Cole the 10 year old

      MARY POPPINS MAN!!

  • BillGates
    Reply

    good job

  • Gail Warren
    Reply

    paradimethylaminobenzaldehyde

    • Alek Sander

      Oooooh good one!

    • Hippopotamus

      Establishmentarianism, establishmentarian, antiestablishmentarianism (don’t know if it’s fully considered a word).

    • Arjun

      Micropachycephalosaurus has 23 letters, too!

  • shelley
    Reply

    wow, looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong English word!

  • Joshua Griffiths
    Reply

    wow good job for pronouncing that long word your amazing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

  • Sam
    Reply

    what about supercalifragilisticexpialidocious?

    • Mujtaba

      It means fantastic

    • Emerald

      The best word around

  • Backnineblues
    Reply

    How about “uncharacteristically”

    • Abimbola

      Yup we’re living in a floccinaucinihilipilification world however it’s supercalifragilisticexpialidocious when life is faithful to us

  • Harry Green
    Reply

    Common long word:

    Uncharacteristically – 20 digits

    • David

      Amorphophalouscompanulatuse

      • Alek Sander

        This is great. The comments are making this the best blog post ever!!!

    • Kevin

      credit for you people commenting and a person who made this

    • Ella

      digits are for numbers, letters are for words

  • XxSmartiexX
    Reply

    floccinaucinihilipilification-the estimation of something as worthless – 29 letters.

    • XxSmartiexX

      sry didnt see it up there

  • IM NOT A ROBOT (OR AM I)
    Reply

    Euouae is the longest word with only vowels.

    • XxSmartiexX

      what does it mean?

    • This Is You

      yeah what it mean

    • Don’t be Lazzzy peeps

      look it up, y’all have internet

    • Hippopotamus

      Euouae (/ju:’u:I:/) or Evovae is an abbreviation used in Latin psalters and other liturgical books to show the distribution of syllables in the differentia or variable melodic endings of the standard Psalm tones of Gregorian chant.

  • Me (AGAIN)
    Reply

    Methionylthreonylthreonylglutaminylarginyl…isoleucine, longest known protien. It has 189,819 letters.

  • Idk
    Reply

    Hexakosioihexekontahexaphobia

    29 characters is the fear of the number 666

    • Anonymous

      =Plz add da protein that has 189819 letters. PLS

      • Alek Sander

        Done!

  • Bobby Bentrus
    Reply

    chlorofluoromethane almost made it! That was funny

  • Paul Nowak
    Reply

    This post was just updated to include videos with pronunciation. Good luck trying to verbalize these words!

  • Unknown
    Reply

    What about PSEUDOPSEUDOHYPOPARATHYROIDISM??

    • Unknown

      Its 30 letters so it would fall as 4th or 5th place in this.

    • Paul Nowak

      Good catch. Updated!

    • Me (AGAIN)

      Methionylthreonylthreonylglutaminylarginyl…isoleucine, longest known protien. It has 189,819 letters. TOO LONG

  • Nancy
    Reply

    I am reading this because of my school compdition ?

  • Jaxson
    Reply

    Wheres Hippopotomonstrosesquipwdaliophobia. It’s 35 letters.

  • georgie
    Reply

    dichlorodiphenyltrichloroethane is 31 letters. It’s a chlorine compound

    • Alek Sander

      That’s a good one. Thanks! We’ll update the post.

  • basher
    Reply

    what About Congratulations ?

  • Harshee Patel
    Reply

    These are words I’ve never heard

    • xXYeahItsMeCreeperXx

      what the @:!? they made that words
      but,How about Marshmallow?

      • Alek Sander

        Marshmallows are delicious!

    • technocrat

      Several of them were really just made up for the purpose of creating ridiculously long words. For example, pneumonoultramicroscopicsilicovolcanoconiosis is not a legit medical word. You won’t find it in any medical dictionary. The words for what it means are pneumoconiosis (pneumonitis caused by fine particles/dust) and silicosis (pneumonitis caused by silicon particles). I’ve seen those 2 combined into pneumosilicosis and *maybe* even pneumosilicoconiosis, but DEFINITELY not the 45 letter version.

  • bob
    Reply

    that is a good word

  • ???
    Reply

    This is a good website but you could also add Antidisestablishmentarianism which has twenty-eight letters and is originally described opposition to the disestablishment of the Church of England, but now it may refer to any opposition to withdrawing government support of a particular church or religion.

    • Paul Nowak

      We have updated our post to reflect your added wisdom! Thank you!

    • @feminoofdips

      Mrs gargantuan
      I caught you here
      ??

  • KAREN BLUMENTHAL
    Reply

    YOU LEFT OUT HIPPOPOTOMONSTROSESQUIPPEDALIOPHOBIA

    FEAR OF LONG WORDS….

    • Oh my goodness

      That’s literally what I came here for… also it’s hippopotomonstrosesquippedaliophobia… that’s too long to write here (0^0)

    • Hannah

      Is that actually a thing

    • bro

      Yes don’t forget hippopotomostreusquippdeloilaphobia

      • Alek Sander

        Thanks! We’ll update the post.

    • Paul Nowak

      Updated. #2 on the list!

    • technocrat

      hippopotomostreusquippdeloilaphobia, like some of the other words on this list, were really just made up for the purpose of creating really long words. The more widely accepted word meaning ‘fear of long words’ is sesquipedalophobia…still long enough to be ironic and funny ;)

    • Cole the 10 year old

      No that was the second one on the list. Or third. Or fourth. I HAVE NO IDEA

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