<P> Pneumonoultramicroscopicsilicovolcanoconiosis (/ ˌnjuːmənoʊˌʌltrəˌmaɪkrəˈskɒpɪkˌsɪlɪkoʊvɒlˌkeɪnoʊˌkoʊniˈoʊsɪs / (listen)) is a word invented by the president of the National Puzzlers' League as a synonym for the disease known as silicosis . It is the longest word in the English language published in a dictionary, the Oxford English Dictionary, which defines it as "an artificial long word said to mean a lung disease caused by inhaling very fine ash and sand dust ." </P> <P> Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs . It is a type of pneumoconiosis . </P>

The longest word in the english language is pneumonoultramicroscopicsilicovolcanoconiosis