The longest word?

What is the longest word in the English language?

I think it is

disenstablishmentarienism

probably mixed up a few letters, but thats what I heard in Science.

Antidisastablishmentarism : ) 25 letters

*Edit*

To katiemariehere

The Mary Poppins word 'Superkalifrajalistikexpialidociuos' isn't in the English Dictionary because it has no meaning.

nope its that one from mary poppins like supercalifragalisticexbealidoshis lol I cant spell for shi* but yeahh when it was added to the dictionary it became the longest one lkke 3 years ago

I would say (supercalafragilisticsexpaladoitios)

hippopotomonstrosesquipedaliophobia
35 letters

And, ironically, is the fear of long words.

Pneumonoultramicroscopicsilicovolcanoconiosis

it has 45 letters, and means lung disease

Pneumonoultramicroscopicsilicovolcanoconiosis

Yes...according to Wiki.

mhrrnbrck and legion are correct I had that for a college class and its the longest word in the english lang and they are correct on the lung disease caused by the inhilation of valcanic ash.

and for everyone else antidisestablishmentarianism is 28 letters long and its the longest word in the english dictionare and the mary poppins thing is just a phrase so not a word its just words scrunched together!