What's the longest ENG. word?

What's the longest English word ? According to the 20 - volume Oxford English Dictionary, the longest word is :Pneumonoultramicroscopicsilicovolcanoconiosis
(it's the name of a lung disease)





圖片參考：http://imgcld.yimg.com/8/n/HA07223432/o/701105310119913873453990.jpg

The longest English word - Smiles