During Ramaḍān, any adult Muslim of sound mind and in good health must abstain from food, drink, smoking, and sexual relations during daylight hours, which are estimated as beginning when ‘the white thread becomes distinct to you from the black thread’ at dawn (Qurʾān 2. 187). It is customary, and recommended, for the Muslim to have a final meal (saḥūr) shortly before daybreak; in the evening the first food (fuṭūr) should be of water or dates, with a large meal following.
"ṣawm." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (August 18, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/sawm
"ṣawm." The Concise Oxford Dictionary of World Religions. . Retrieved August 18, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/sawm