The correct answer is pneumonoultramicroscopicsilicovolcanoconiosis.
Explanation:
The word pneumonoultramicroscopicsilicovolcanoconiosis is an artificial word that supposedly means, "lung disease caused by inhaling very fine silica dust, causing inflammation in the lungs." It is used mainly as an example when speaking of very long words.
A disease that meets the definition of the word is commonly called silicosis.
The 45-letter word was coined to be the longest in the English language. It is, in fact, the longest word to appear in an English dictionary, found in current editions of several dictionaries. It is usually abbreviated with the number P45.
