longest word

The question of what is the longest English word is an old chestnut, and one with a variety of possible answers.

As above, there are many (perhaps infinitely many) exceptionally long words possible as chemical names, by combining any number of prefixes and/or suffixes to give a descriptive name for a complex molecule.

The longest word to make it into any standard dictionary is pneumonoultramicroscopicsilicovolcanoconiosis (also spelled pneumonoultramicroscopicsilicovolcanokoniosis. This is supposedly name for a form of a miners' disease (silicosis) caused by extremely small volcanic dust.

However, this word is believed to have been coined by word puzzlers, and still reeks of technical jargon.

Most of the other top candidates are also of doubtful origin, though. There are others that top out around 28 letters, such as floccinaucinihlipilification (coined from 4 Latin words meaning "nothing"), and antidisestablishmentarianism (a coinage meaning a philosophy of opposition to breaking the existing establishment). Electrophotomicrographically is perhaps legitimate.

This subject came up when I was reading alt.usage.english many years ago.
The original thread was spawned by the juvenile riddle to which the correct answer is:

Smiles

Why? Because there's a mile between the first and last letters.

A prompt response from one poster was that Beleaguered must therefore be a longer word
since a league is three miles.

That was when the thread took off:
"That doesn't count because it requires you to add too many letters."
"laud is longer, because the AU it contains is an astronomical unit!"
"In that case glyph contains a light year!"
"Abbreviations don't count!"
"She spelt Beleagered wrong!"
and so on and so forth.

Longest word used by William Shakespeare:

honorificabilitudinitatibus

This Shakespearian word comes from Love's Labour's Lost
V.i. Shakespeare did not coin this word, however.
It is actually the ablative plural of the Latin
honorificabilitudinitas, which is an extension of
honorificabilis meaning 'honorableness'. It first
occurs in English in 1599, used by Thomas Nashe.

Longest Word in the English Language Dictionary

At 45 letters Pneumonoultramicroscopicsilicovolcanoconiosis is the longest non-scientific/place-name word in any English language dictionary.

The word appears in the 1936 Supplement to OED1, the OED2, the addendum to W2 (spelled -koniosis), W3 (spelled -coniosis), RHUD2, and Chambers.

The OED2 has:

• pneumonoultramicroscopicsilicovolcanoconiosis (-koniosis), a factitious word alleged to mean 'a lung disease caused by the inhalation of very fine silica dust' but occurring chiefly as an instance of a very long word.
• 1936 F. Scully Bedside Manna 87 *Pneumonoultramicroscopicsilicovolcanakoniosis sic, a disease caused by ultra-microscopic particles of sandy volcanic dust, might give even him laryngitis.
• 1966 Word Study Oct. 7/2 The resources of Greek have enriched the modern world as well as the ancient one. Perhaps this is most dramatically illustrated by the longest and most fantastic word now in an English dictionary (the Merriam-Webster’s great Unabridged) which is forty-five letters in length: pneumonoultramicroscopicsilicovolcanoconiosis,..meaning 'a disease of the lungs caused by extremely small particles of ash and dust'.
• 1973 R. Megarry Second Miscellany-at-Law 160 It has been said that 'floccinaucinihilipilification' is the longest word in the English language... The word’s proud title must yield to some technical terms, such as pneumonoultramicroscopicsilicovolcanokoniosis.

Click here for links to the English Language.

What is the world's longest word?

A difficult question. Some good candidates for English have already been noded up, but for most other languages you have to limit the question a bit more.

First of all, compound words are not fair game, since many languages (like German) can pile them up to near-infinite length. Alas, this disqualifies many family favorites like Hottentottenpotentatenattentat ("an attempt to assassinate a Pygmy regent"). Nearly all those really long place names are also compound words.

Second, chemical names are not really acceptable either, since they're essentially compound words built out of Greek, more or less equivalent to reading out "hydrogen and carbon and hydrogen and oxygen and carbon and hydrogen and..." in English. So we have to disqualify these too.

Next, we have the issue of agglutinative versus non-agglutinative languages. Instead of English-style helper words ("of", "by", "your", "through"...), agglutinative languages add prefixes and suffixes to word stems, resulting in hideously long words if you just conjugate them enough. One classic example is the Turkish Afyonkarahisarlılaştıramadıklarımızdanmısınız ("Aren't you one of those people whom we tried, unsuccessfully, to make resemble the citizens of Afyonkarahisar?") -- although this contain a proper noun and is thus a bit iffy. Some people disqualify these too, because you obviously won't find the conjugated forms in a dictionary, but most people think they qualify.

And thus, according to some editions of the Guinness Book of World Records, the world's longest word is the following Finnish monster:

epäjärjestelmällistymättömyydellänsäkäänköhän

But what does it mean?

Let's analyze, step by step:

epä "un-"
järjestelmä "system"; from järki, reason, via järjestää, to organize
llis adjective indicator
t causative, action from outside
yttä "-zation", becoming something
mä noun indicator
ttöm from -ttä, "-less", abessive case
yyde from -yys, "-ness", quality of being something
llä "using", adessive case
n "with", instructive case
sä 3rd person possessive case
kään "also"
kö question indicator
hän "I wonder?"

Note: I'm not a grammarian and I've probably got some of those wrong, corrections are welcome. Finnish cases all conjugate happily into each other, mutating as they go along, so disentangling something as purposely perverse as this word isn't easy...

Yeah yeah, but what does it MEAN?

(I was hoping I wouldn't have to answer that.)

This is a sentence fragment, mind you, so I need to add a blank in the middle in order to transform it into English:

Wonder if he can also ... with his capability of not causing things to be unsystematic?

Or something along those lines. A very useful word indeed, yes?

Could you make something even longer?

But of course, and I believe some later attempts have made it past the 100-letter mark. The word above is undoubtedly the most famous of the bunch though, because unlike the longer candidates it still remains barely comprehensible.

However, Finnish also has a method of generating infinitely long non-compound words through a peculiar recursive verb construction. Here's an example, using the verb tehdä ("to do"):

N  Verb          Meaning
0  tehdä         to do
1  teettää       to have someone do
2  teetättää     to have someone have someone do
3  teetätättää   to have someone have someone have someone do
   ...
N  tee(tä)Nttää  to (have someone)N do

The N=2 form is occasionally used even in real life, but forms beyond that aren't spotted too often. Still, they are grammatically perfectly valid Finnish, and thus the N=∞ form is and shall remain the longest word in the world.

Much of this used to be noded under epäjärjestelmällistymättömyydellänsäkäänköhän, which screwed up softlinks with its length and was thus nuked.