最長的英文字是甚麼字？

We do have genuine (if rather obviously deliberate) examples in our files of antidisestablishmentarianism (28 letters) and floccinaucinihilipilification (29 letters), which are listed in some of our larger dictionaries. Other words (mainly technical ones) recorded in the complete Oxford English Dictionary include:

otorhinolaryngological (22 letters),
immunoelectrophoretically (25 letters),
psychophysicotherapeutics (25 letters),
thyroparathyroidectomized (25 letters),
pneumoencephalographically (26 letters),
radioimmunoelectrophoresis (26 letters),
psychoneuroendocrinological (27 letters)
hepaticocholangiogastrostomy (28 letters),
spectrophotofluorometrically (28 letters),
pseudopseudohypoparathyroidism (30 letters).

Most of the words which are given as 'the longest word' are merely inventions, and when they occur it is almost always as examples of long words, rather than as genuine examples of use.

ah, if you guys know , the longest English word in the world has 1909 letters.
It is true since it has been recored in the Guiness Book and this is mentioned in some (HK)F.1 english textbooks as well.
However, I can't spell it. Sorry for that.

其實，pneumonoultramicroscopicsilicovolcanoconiosis（即火山肺矽病），它是最長的英文單字，總共由45個英文字母組合而成。

I think you are giving us a riddle, do you?

My answer is: smiles

The longest word in any major English language dictionary is pneumono­ultra­micro­scopic­silico­volcano­coniosis, a 45-letter word supposed to refer to a lung disease contracted from the inhalation of fine silica dust, but research has discovered that this word was originally intended as a hoax. It has since been used in a close approximation of its originally intended meaning, lending at least some degree of validity to its claim.[1]

The Oxford English Dictionary contains pseudopseudohypoparathyroidism (30 letters).

2007-03-09 12:14:30 補充：
http://www.askoxford.com/asktheexperts/faq/aboutwords/longestwordradioimmunoelectrophoresis (26 letters), psychoneuroendocrinological (27 letters) hepaticocholangiogastrostomy (28 letters), spectrophotofluorometrically (28 letters), pseudopseudohypoparathyroidism (30 letters).