The spelling of the word "UNO FLATU" may seem confusing at first, but it can be easily explained using the International Phonetic Alphabet (IPA). "UNO" is spelled /ˈuːnəʊ/ with a long "u" sound and a silent final "e". "FLATU" is spelled /ˈflætjuː/ with a long "a" sound and a "t" followed by a "j" sound. Combined, the word is pronounced as /ˈuːnəʊ ˈflætjuː/ or "OON-oh FLAH-too". The word itself means "one flatulence" and is often used humorously to refer to a single instance of passing gas.