What is the definition of pneumanultramicroscopic-siliconvolcanicanisis?

Answer 1

It is a long name for a form of the lung disease "silicosis". The word was created in 1935 at the National Puzzlers Convention with the aim of being the longest dictionary word. It did not succeed for the most part but is often promoted as "the longest word in the English language" at 45 letters (the hyphen is added here to allow it to display).