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Pneumonoultramicroscopicsilicovolcanoconiosis (45 letters) is the ninth longest word in English, it means a lung disease, this is also longest word in a major dictionary. From Oxford English Dictionary: “[this is] a factitious (i.e., created by humans, artificial) word alleged to mean a lung disease caused by the inhalation of very fine silica dust causing inflammation in the lungs. Occurring chiefly as an instance of a very long word.”

Let us investigate the word more carefully. First, we come to the prefix (pneu-), or (pneumo-) which means lung. Next, is ultra, meaning extreme, and microscopic, meaning small. Now we come to (silico-), which refers to silicon, and (volcano-) which refers to the mineral particles that make up a volcano. Then we have (coni-), a derivative of the Greek word konis meaning dust. Finally, we have the suffix (-osis) which means affected with. Now lets rebuild what we have dissected:

Considering the prefix (pneumo-) and the suffix (-osis), we can determine that the lungs are affected with something. But what? Breaking down the rest of the terms we get extremely small (ultramicroscopic) silicon (silico-) and volcanic (volcano-) dust (coni-) particles. Thus, pneumonoultramicroscopicsilicovolcanoconi-osis is a disease of the lungs resulting from the inhalation of very fine silicate or quartz dust. That’s all. (taken from

You can find more info about pneumonoultramicroscopicsilicovolcanoconi-osis here. Let me finish the article with such illustration:


Longest Words in English Top 14:


One Comment

  1. what a word ….pnuemonoultramicroscopicsiliconvolcanicconusis

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