The longest word in the English dictionary is pneumonoultramicroscopicsilicovolcanconioisi

The+longest+word+in+the+English+dictionary+is+pneumonoultramicroscopicsilicovolcanconioisi

By: Patrick Coveny, Fall Editor and Reporter

Pneumonoultramicroscopicsilicovolcanconioisi has 45 letters and is a lung disease caused by inhaling ash.