Pneumonoultramicroscopicsilicovolcanoconiosis is the longest word in the English language. The word contains 45 letters, earning it the nickname “P45.”

Pneumonoultramicroscopicsilicovolcanoconiosis is defined as, “‘a lung disease caused by the inhalation of very fine silica dust.” Silicosis is its often-used synonym.

I haven’t put this word in my dictionary yet. I’m not sure if I ever will. Has anyone ever heard this word uttered during a court proceeding, or deposition? I couldn’t imagine what my reaction would be. Lol.