“Methionylalanylthreonylserylarginylglycyl…” and ending with “…leucine”, the longest word contains 189,819 letters!
This word is the name of a protein found in our muscles that keeps them elastic. A protein’s name lists every single amino acid found inside it. Smaller proteins contain about 20 amino acids and this particular one contains 34,350! It is the human body’s largest protein – listing out all the amino acids is what causes its long name.
Most scientists themselves won’t be found naming it in whole, preferring to abbreviate it to ‘Titin’. However, being a scientific term, it’s not found in any dictionary. Ironically, one of the longest words is a synonym for a shorter word, deliberately made long to mock long complicated scientific names. Pneumonoultramicroscopicsilicovolcanoconiosis is another name for silicosis (a lung disease) and is 45 letters long.
The next longest word in the Oxford English Dictionary is supercalifragilisticexpialidocious, something anyone who’s seen Mary Poppins is familiar with. It’s defined as being “extraordinarily good”, though it’s more of a nonsense word. It’s 34 letters.
The longest word published in many dictionaries was Antidisestablishmentarianism though some ictionaires like Merriam-Webster don’t have it due to long-term lack of use. It was used to refer a 19th century political party opposed to the disestablishment of the Church of England. It’s 28 letters.
In our text-message generation where most communication is aided by abbreviations and words are constantly being made shorter, it’s not surprising that dictionaries are removing ancient unused long words.