What is a Mosque?
A mosque is the house of worship in Islam. The Arabic word is masjid, meaning 'place of prostration', because the central act performed there is sujūd, the bowing of the forehead to the ground in prayer. Any clean space can serve, but the typical mosque is a building oriented toward Mecca, where Muslims gather for the five daily prayers and the main Friday congregation.
Mosque vs church, temple and synagogue
A mosque is often compared to a church, a synagogue or a Hindu temple, and the differences are instructive. A church or synagogue is built around an altar, an ark or a focal sanctuary. A Hindu temple houses the image of a deity in an inner shrine. A mosque has no altar, no clergy in the priestly sense, and almost never any image of God or of living beings. Islamic practice is largely aniconic. What orients the space is not a picture but a direction: the miḥrāb, a niche set into the wall that marks the qibla, the line toward the Kaʿba in Mecca that every worshipper faces.
The mosque is also not a Sufi lodge. The communal prayer of the mosque belongs to mainstream Islam and its outer law. The gathering for dhikr, the repeated remembrance of God taught in Sufism, often happens in a separate space called a zāwiya or tekke, though in practice the two have always overlapped.
What it is and how it is used
The institution goes back to the beginnings of Islam in the seventh century. Tradition names the Quba Mosque in Medina, built after Muhammad's emigration from Mecca in 622 CE, as the first structure raised for the purpose. The sanctuary around the Kaʿba in Mecca, the Masjid al-Ḥarām, is held to be older still. The early mosque was plain: an open courtyard with a shaded portico. Over the centuries it acquired its recognisable features. The minaret is a tower from which the call to prayer (adhān) is given. The minbar is a stepped pulpit from which the Friday sermon is delivered. To these are added the miḥrāb niche and a facility for the ritual washing (wuḍūʾ) performed before prayer.
Five times a day a mosque may host congregational prayer, but the obligation that gathers the largest crowd is the Friday midday prayer, jumʿah, which includes a sermon. The leader of the prayer is the imām, who in Sunni practice is not an ordained priest but a member of the community chosen to lead. Outside prayer, mosques have long served as schools, courts, libraries and shelters. The great congregational mosque of a city, the jāmiʿ, was historically its civic centre as much as its religious one.
Aniconism, geometry and the question of images
Because figurative depiction of God and, in much of the tradition, of living beings is avoided in the mosque, its decoration developed in other directions: calligraphy of Qurʾanic verses, vegetal arabesque, and the interlocking patterns often discussed under the heading of sacred geometry. How strict this aniconism is has never been settled. The Qurʾan itself contains no blanket ban on images; the prohibition is drawn mainly from hadith and has been read more and less strictly across regions and centuries. Persian and Mughal art, for instance, produced figurative painting outside the mosque. The lexicon notes this as a live scholarly and legal disagreement within Islam, not a fixed rule, and takes no side. The contrast with the image-centred iconography of Orthodox Christianity is one of the clearest dividing lines between the two.
Where it sits in the index
The index covers Islam mainly through its mystical current, Sufism, and the poets and teachers around it. The mosque is the ordinary, public counterpart to that inner path: the place where the daily prostration and the communal prayer happen, as distinct from the dhikr of the orders. It also belongs to the wider family of sacred places the index treats under pilgrimage, the Masjid al-Ḥarām in Mecca being the destination of the ḥajj, the pilgrimage every able Muslim is enjoined to make once in a lifetime.