An ubosot (Thai: อุโบสถ `ubōsot IPA: [ʔùʔ boː sòt][1]), phra ubosot (Thai: พระอุโบสถ; phra `ubōsot IPA: [pʰráʔ ʔùʔ boː sòt];[1] Pronunciation) or, for short, bot (Thai: โบสถ์; bōt IPA: [bòːt];[1] Pronunciation) is a building in a Buddhist wat. It is the holiest prayer room, also called the "ordination hall" as it is where ordinations take place.
The term ubosot, shortened to bot in Thai colloquial speech, is derived from the Pali term uposathagara, which refers to a hall used for rituals on the uposatha days -- the Buddhist Sabbath, which falls four times a month on the full moon, new moon, and eighth day after each.[2]