What is the world longest word?

The longest word would depend on your definition of what a word in the English language is. There is a chemical name that is 189,819 letters but it is truly disputed. But the longest word in a major dictionary is 45 letters long. It's Pneumonoultramicroscopicsilicovolcanoconiosis. For more information see here: http://www.fun-with-words.com/word_longest.html

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