Ḥaram (Arabic: حَرَم, Holy Shrine), is an area that includes a holy place, and has a special holiness because of what it includes.
The most important haram for Muslims is al-Haram al-Makki in which Ka'ba and al-Masjid al-Haram are located. The next important haram is al-Haram al-Madani that involves the Prophet's house and tomb (al-Masjid al-Nabawi). These two are called al-Haramayn al-Sharifayn (the two shrines) among Muslims.
In a broad meaning, haram is also used for the holy shrine of Imams (a) and even for the descendants of Imams. The terms al-haram al-'Alawi, al-haram al-Husayni are used in accordance with this broad meaning. Haram, among Shi'a, is used for the Masjid or building which is built around a tomb.
One of the especial rulings of al-Masjid al-Haram, the shrine of the Prophet (s), shrine of Imam al-Husayn, and Mosque of Kufa is that pilgrims coming from other places are allowed and even recommended to do their prayers in the complete form, even though travelers normally have to do they prayers in short form.