Narrated Abu Huraira:
Allah’s Messenger (peace be upon him) said, “The prayer of a person who does Hadath (passes urine, stool or wind) is not accepted till he performs the ablution.” A person from Hadaramout asked Abu Huraira, “What is ‘Hadath’?” Abu Huraira replied, ” ‘Hadath’ means the passing of wind.”
(Bukhari Vol. 1, Book 4, Hadith 137)