The word Islam is a transliteration of the Arabic ﺇﺳﻼﻢ, (islām), which means ‘surrender, submission’ – though in Arabic when referring to Islam it is always used with the definite article, اﻹﺴﻼﻢ (al-islām). The word is a noun from the verb ﺃﺳﻠﻢ (aslama), which means ‘to surrender, resign, or commit oneself (to the will of Allah)’, ‘to become a Muslim’. A Muslim, i.e., an adherent of Islam, is in Arabic ﻣﺴﻠﻢ (muslim), which is also from the verb ﺃﺳﻠﻢ (aslama), and means ‘one who surrenders, has surrendered (to Allah)’.
While there are many differences of belief and practice within Islam – see further, e.g., Sunni - Shia – all Muslims believe that there is one god, Allah, and that Muhammad (c570-632 CE) is his messenger. They believe that their fundamental religious text, the Qur’an (sometimes spelt Koran) (ﺍﻟﻘﺮﺁﻥ, al-gur’ān, ‘recitation’, from ﻗﺮﺃ, qara’a, ‘to read’, ‘to recite’, ‘to read out loud’) is a verbatim record of the messages communicated by Allah to Muhammad, but they also accord authority - different branches of Islam to different degrees.- to the Hadith (ﺍﻟﺤﺪﻴﺚ, al-hadith), the accounts by Muhammad’s contemporaries of his life, practice, and teaching.
All Muslims recognise five religious duties: to bear witness to their faith (شهادة, shahadah),; to pray (for Sunnis five times a day, for Shias three times a day) (صلاة, salah); to give alms to the poor (زكاة, zakah); to fast (from sunrise to sunset) during the (Arabic) month of Ramadan (صوم, sawm); and to make the pilgrimage to Mecca (حج, hajj). Sunnis refer to these five religious duties as the Five Pillars (of Islam); Shias understand the Five Pillars in a different way (see Sunni - Shia).
Festivals are more numerous in Shia than in Sunni Islam, but all Muslims recognise two festivals: The Feast of Breaking the Fast, eid al-fitr (ﻋﻴﺪ ﺍﻟﻔﻄﺮ, sometimes known as The Lesser Feast, ﺍﻟﻌﻴﺪ ﺍﻟﺼﻐﻴﺮ (al-eid as-saghir)), celebrated at the end of Ramadan; and the Feast of the Sacrifice, eid al-adha (ﻋﻴﺪ ﺍﻷﻀﺤﻰ, sometimes known as The Great Feast, ﺍﻟﻌﻴﺪ ﺍﻟﻜﺒﻴﺮ (al-eid al-kabir)), celebrated over three days from the twelfth day of the (Arabic) month of Dhu al-hijjah, during which a sheep is sacrificed and its meat distributed among family, friends, and the poor.
Muslims, of whom there are currently (2017) about 1.8 billion, constitute nearly a quarter of the world’s population. They are found principally in the Middle East, Indonesia, South-east Asia, and North Africa, but there are also significant numbers in other parts of the world.