It's called Rajam

Tehran, 10 July (AKI) - Jafar Kiani has been stoned to death in Takestan, in Iran's north-western province of Qavzin, at the order of a local Islamic judge. The death sentence by stoning against Kiani and his partner Mokarrameh Ebrahimi, with whom he had cohabited out of wedlock for 13 years, has been suspended after a widespread international campaign by human rights activists on behalf of the couple convicted of adultery.

The execution, which took place despite the reported opposition of the Islamic Republic's central judicial authorities, has stunned Iranian activists who champion a moratorium on capital punishment by stoning.

Activists now fear that Ebrahimi, who has an 11-year-old child by Kiani, will also be stoned.

The Islamic Penal Code of Iran allows for the punishment of death by stoning for crimes of adultery.

In December 2002, Ayatollah Mahmud Hashemi Shahrudi, the head of Iran’s judiciary, ordered a ban on stoning. Despite this, lapidation continues, and it is disproportionately applied to women, despite campaigning by Iranian women’s rights activists, human rights groups have denounced.
http://www.adnkronos.com/AKI/English/Security/?id=1.0.1095027621

Linguistically, hudud in Arabic means limits or preventions. Legally, they are limits, which prevent the crime from increasing in society, prevent the criminal from going back to similar crimes, and prevent those who think about the same crime from pursuing it. Hudud in this sense are not merely punishments, on the contrary, they are limits and preventive means placed within a larger framework of justice, related directly to the interests of people to serve the ultimate objectives of the Islamic law.

The punishment system in Islam has concerns that Muslims need to be aware of. It concerns that are aimed toward the three dimensions of any crime: the criminal (the one who carried out the act), the society (where the crime took place) and the victim (the one who was subject to the criminal act). These objectives are:

1. To criminals, punishment is kaffara (purification) and reforming for the re-acceptance into the society.

2. To society, punishment is a preventive method to save the society from crimes.

3. To victims, punishment is a mean of retribution.

http://www.irfi.org/articles/articles_51_100/zina_and_rajm.htm

“Imran b. Hussein reported that a woman from Juhaina came to Mohammed and said she had become pregnant because of adultery. She said: ‘I am pregnant as a result of Zina.’ Mohammed said: ‘Go back, and come to me after the birth of the child.’ After giving birth, the woman came back to Mohammed, saying: ‘Please purify me now.’ Next, Muhammad said, ‘Go and suckle your child, and come after the period of suckling is over.’ She came after the period of weaning and brought a piece of bread with her. She fed the child the piece of bread and said, ‘O, Allah's Apostle, the child has been weaned.’ At that Muhammad pronounced judgment about her and she was stoned to death.” “The Book Pertaining to Punishments Prescribed by Islam (Kitab Al-Hudud).” Sahih Muslim, B. 17, N. 4207. USC-MSA, Compendium of Muslim Texts.

“Allah sent Muhammad with the Truth and revealed the Holy Book to him, and among what Allah revealed, was the Verse of the Rajam (the stoning of married person (male & female)) who commits illegal sexual intercourse, and we did recite this Verse and understood and memorized it. Allah's Apostle did carry out the punishment of stoning and so did we after him.

I am afraid that after a long time has passed, somebody will say, 'By Allah, we do not find the Verse of the Rajam in Allah's Book,' and thus they will go astray by leaving an obligation which Allah has revealed. And the punishment of the Rajam is to be inflicted to any married person (male & female), who commits illegal sexual intercourse, if the required evidence is available or there is conception or confession.” Sahih Bukhari, Book 82: Volume 8, Number 817: Narrated Ibn 'Abbas. www.usc.edu/.

It's nice having an annotated glossary at hand.