| Main Entry: | pneumonoultramicroscopicsilicovolcanoconiosis |
| Part of Speech: | n |
| Definition: | supposedly the longest word in a dictionary, an artificial word said to mean a lung disease caused by the inhalation of silica dust |
| the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language). |
| a white, crystalline, water-insoluble solid, C14H9Cl5, usually derived from chloral by reaction with chlorobenzene in the presence of fuming sulfuric acid: used as an insecticide and as a scabicide and pediculicide: agricultural use prohibited in the U.S. |