It is the ninth month of the Islamic calendar and is observed by Muslims worldwide as a month of fasting from food or drink from sunrise to sundown to commemorate the first revelation of the Quran to the prophet Muhammad. This annual observance is regarded as one of the Five Pillars of Islam. The word Ramadan comes from the Arabic root ramiḍa or arramaḍ, which means scorching heat or dryness. Fasting is obligatory for adult Muslims, except those suffering from an illness, travelling, who are elders, pregnant, and other conditions. For some Muslims, naked-eye sighting of the location of the moon determines the start of the observance. Two possible days for the start of fasting are noted to avoid confusion. (1. Please note that some clients and employees may be fasting from sun-up to sun-down for an entire month. 2. Date is the first day of the celebratory period. 3. Observance begins at sunset the day prior.)