Respuesta :

Pneumonoultramicroscopicsilicovolcanoconiosis: "A lung disease contracted from the inhalation of very fine silica particles, specifically from a volcano; medically, it is the same as silicosis."
Hope this helps~!
~{Dunsforhands}
the longest word in the dictionary is pneumonoultramicroscopicsilicovolcanoconiosis meaning 

a pneumoconiosis caused by inhalation of very fine silicate or quartz dust

Hope I helped if i did plz mark me the best! have a good day : D