Eid al-Adha (Arabic: عيد الأضحى‎ ‘Īdu l-’Aḍḥā) "Festival of Sacrifice" or "Greater Eid" is a Muslim Holiday celebrated by Muslims (including the Druze) worldwide to commemorate the willingness of Ibrahim to sacrifice his son Ismael as an act of obedience to God.

Eid al-Adha is the latter of two Eid festivals celebrated by Muslims, whose basis comes from the Quran.(Muslims who belong to the Shi'ite branch of Islam celebrate a third Eid.) Like Eid al-Fitr, Eid al-Adha begins with a short prayer followed by a sermon (khuṭba).
Eid al-Adha annually falls on the 10th day of the month of Dhul Hijja (ذو الحجة) of the lunar Islamic calendar.

The festivities last for three days or more depending on the country. Eid al-Adha occurs the day after the pilgrims conducting Hajj, the annual pilgrimage to Mecca in Saudi Arabia by Muslims worldwide, descend from Mount Arafat. It happens to be approximately 70 days after the end of the month of Ramadan.

The Arabic term "Festival of Sacrifice", ‘Īd ul-’Aḍḥā was borrowed as a unit into Indic languages such as Hindi, Urdu, Gujarati and Bengali and Austronesian languages such as Malay and Indonesian.

Another Arabic word for "sacrifice", (Arabic: قربان‎ Qurbān), was lent into Dari Persian and Iranian dialect of Persian as Eyde Ghorbân (Persian: عید قربان), into Tajik Persian as Иди Қурбон Idi Qurbon, into Kazakh as Құрбан айт (Qurban ayt), into Uyghur as Qurban Heyit, and also into various Indic languages. Other languages combined the Arabic word qurbān with local terms for "festival", as in Kurdish (Cejna Qurbanê), Pashto (Kurbaneyy Akhtar), Chinese (Chinese: 古尔邦节 Gúěrbāng Jié), Malay and Indonesian (Hari Raya Korban, Qurbani), and Turkish (Turkish: Kurban Bayramı). The Turkish term was then later borrowed into languages such as Azeri (Qurban Bayramı), Tatar (Qorban Bäyräme), Bosnian, (Kurban Bajram), Serbian (Курбан бајрам), Russian (Курбан байрам).

Another Arabic name, ‘Īd ul-Kabīr (Arabic: عيد الكبير‎ `Īd al-Kabīr), meaning "Greater Eid/Festival", is used in Yemen, Syria, and North Africa (Morocco, Algeria, Tunisia, Libya, and Egypt). The term was borrowed directly into French as Aïd el-Kebir. Translations of "Big Eid" or "Greater Eid" are used in Pashto لوی اختر Loy Akhtar, Kashmiri Baed Eid, Hindi and Urdu Baṛā Īd, Malayalam Bali Perunnal, and Tamil Peru Nāl.

Another name refers to the fact Eid-al-Adha has other popular names across the Muslim world. The name is often simply translated into the local language, such as English Festival of Sacrifice, German Opferfest, Dutch Offerfeest, and Hungarian Áldozati ünnep.

that the holiday occurs after the culmination of the Hajj (حج), or pilgrimage to Mecca (Makka). Such names are used in Malay and Indonesian (Hari Raya Haji "Hajj celebration day", Lebaran Haji), and in Tamil Hajji Peru Nāl.

In Hindi- and Urdu-speaking areas, the festival is also called بقرعید Baqra Īd or Baqrī Īd, stemming either from the Arabic baqarah "heifer" or the Urdu word baqrī for "goat", as cows and goats are among the traditionally-sacrificed animals. That term was also borrowed into other languages, such as Tamil Bakr Eid Peru Nāl.

Other local names include 宰牲节 Zǎishēng Jié ("Slaughter-livestock Festival") in Chinese, Tfaska Tamoqqart in the Berber language of Jerba, Tabaski or Tobaski in West African languages,Babbar Sallah in Nigerian languages, and Ciidwayneey in Somali.

History
Four thousand years ago, the valley of Mecca was a dry and uninhabited place. According to Islamic history, the Prophet Ibrahim (Abraham) was instructed to bring his wife Hajar (Hajira) and their child Ismael to Arabia from the land of Israel - Canaan - by God's command, as his childless first wife Sarah had become jealous that Hajar bore a child and she had not.

As Ibrahim made ready to return to the land of palestine, his wife Hajar asked him: "Who ordered you to leave us here"? When Ibrahim replied: "God", Hajar said: "then God will not forget us; you can go". Although Ibrahim had left a large quantity of food and water with Hajar and Ismael, the supplies quickly ran out and within a few days the two were suffering from hunger and dehydration.

According to the story, a desperate Hajar ran up and down two hills called Safa and Marwa seven times, trying to see if she could spot any help in the distance. Finally she collapsed beside her baby Ismael and prayed to God for deliverance. Ismael struck his foot on the ground, and this caused a spring of water to gush forth from the earth. With this secure water supply, they were not only able to provide for their own needs, but were also able to trade water with passing nomads for food and supplies. When the Prophet Ibrahim returned from Canaan to check on his family, he was amazed to see them running a profitable well.

The Prophet Ibrahim was told by God to build a shrine dedicated to him adjacent to Hajar's well (the Zamzam Well). Ibrahim and Ismael constructed a small stone structure–-the Kaaba--which was to be the gathering place for all who wished to strengthen their faith in God. As the years passed, Ismael was blessed with Prophethood and he gave the nomads of the desert his message of surrender to God--the Islamic faith. After many centuries, Mecca became a thriving city thanks to its reliable water source, the well of Zamzam.

In the year 628 the Prophet Muhammad set out on a journey with 1400 of his followers. This was the first pilgrimage in Islam, and would re-establish the religious traditions of the Prophet Ibrahim.

Traditions and practices
Men, women, and children are expected to dress in their finest clothing to perform Eid prayer (ṣalātu l-`Īdi) in a large congregation in open area (not in a mosque). Muslims who can afford to do so sacrifice their best domestic animals (usually sheep, but also camels, cows and goats) as a symbol of Ibrahim's sacrifice.

The sacrificed animals, called uḍiyyah (Arabic: أضحية‎, also known as "al-qurbāni"), have to meet certain age and quality standards or else the animal is considered an unacceptable sacrifice. Generally, these must be at least a year old. The regular charitable practices of the Muslim community are demonstrated during Eid al-Adha by the concerted effort to see that no impoverished person is left without sacrificial food during these days.

Distributing meat among people is considered an essential part of the festival during this period, as well as chanting Takbir out loud before the Eid prayer on the first day and after prayers through out the four days of Eid. (See Takbir in "Traditions and practices" of Eid el-Fitr.) In some countries families that do not own livestock can make a contribution to a charity that will provide meat to those who are in need.

Eid al-Adha in the Gregorian calendar
See also: Islamic calendar
While Eid al-Adha is always on the same day of the Islamic calendar, the date on the Gregorian calendar varies from year to year since the Islamic calendar is a lunar calendar and the Gregorian calendar is a solar calendar. The Lunar calendar is approximately eleven days shorter than the Solar calendar. Each year, Eid al-Adha (like other Islamic holidays) falls on one of two different Gregorian dates in different parts of the world, due to the fact that the boundary of crescent visibility is different from the International date line.

The following list shows the official dates of Eid al-Adha for Saudi Arabia as announced by the Supreme Judicial Council. Future dates are calculated according to the Umm al-Qura calendar of Saudi Arabia. The three days after the listed date are also part of the festival. The time before the listed date the pilgrims visit the Mount Arafat and descend from it after sunrise of the listed day. Future dates of Eid al-Adha might face correction 10 days before the festivity, in case of deviant lunar sighting in Saudi Arabia for the start of the month Dhul Hijja.