Ṣalāh is one of the Five Pillars of the faith of Islam and an obligatory religious duty for every Muslim. It is a physical, mental and spiritual act of worship that is observed five times every day at prescribed times. In this ritual, the worshiper starts standing, bows, prostrates, and concludes while sitting on the ground. During each posture, the worshiper recites or reads certain verses, phrases and prayers. The word salah is commonly translated to prayer but this definition might be confusing. Muslims use the words "Dua" or "Supplication" when referring to the common definition of prayers which is "reverent petitions made to God."Salah is preceded by ritual ablution. Salah consists of the repetition of a unit called a rakʿah (pl. rakaʿāt) consisting of prescribed actions and words. The number of obligatory rakaʿāt varies from two to four according to the time of day or other circumstances (such as Friday congregational worship, which has two rakats). Prayer is obligatory for all Muslims except those who are prepubescent, menstruating, or are experiencing bleeding in the 40 days after childbirth.TerminologySalah is an Arabic word whose basic meaning is "bowing, homage, worship, prayer." In its English usage, the reference of the word is almost always confined to the Muslim formal, obligatory worship described in this article.Translating salah as "prayer" is not usually considered precise enough, as "prayer" can indicate several different ways of relating to God; personal prayer or supplication is called duʿāʾ in Islamic usage.