Popsugar Living Science News Facts That Will Surprise You 10 Mind-Boggling Facts That You Probably Don't Know February 12, 2018 by Nicole Yi View On One Page Photo 7 of 10 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 7 The longest English word is pneumonoultramicroscopicsilicovolcanoconiosis. This 45-letter word is a lung disease caused by inhalation of silicate or quartz dust. Previous Next Start Slideshow Science NewsRedditFun Facts