What is the beleiving of the longest word?

Do you mean (what is the longest Word that everyone beleive's in? Well the maori's think it's Taumatawhakatangihangakuayuwotamateaturipukakupikimaungahoronukupokaiawhenuakatanatahumatakuatanganuakawamikitora.

If it is not then the second one would have to be Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch. Ifnot that either thansorry i can not help you.