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. (Definition retrieved from Oxford English Dictionary)
Pneumonoultramicroscopicsilicovolcanoconiosis is notable for causing respiratory problems as well as unnecessary fatigue and frustration at spelling bees.
Person A: Hey, guess what? I can spell the longest word ever! *Spells out pneumonoultramicroscopicsilicovolcanoconiosis.*
Person B: Dude, get a life...
A medical term to describe a lung disease. Caused by inhaling very fine sand and ash. It is a type of pneumoconiosis, which also means the accumulation of dust in the lungs.
I inhaled very small silica dust from the large volcano and it caused me to contract Pneumonoultramicroscopicsilicovolcanoconiosis of the lungs.