Sanctuary

A sanctuary, in its original meaning, is a sacred place, such as a shrine. By the use of such places as a haven, by extension the term has come to be used for any place of safety. This secondary use can be categorized into human sanctuary, a safe place for humans, such as a political sanctuary; and non-human sanctuary, such as an animal or plant sanctuary.

Sanctuary is a word derived from the Latin sanctuarium, which is like most words ending in -arium, a container for keeping something in—in this case holy things or perhaps holy people, sancta or sancti. The meaning was extended to places of holiness or safety. A religious sanctuary may be a sacred place (such as a church, temple, synagogue or mosque), or a consecrated area of a church or temple around its tabernacle or altar.

In Europe, Christian churches were sometimes built on land considered to be a particularly holy spot, perhaps where a miracle or martyrdom was believed to have taken place or where a holy person was buried. Examples are St. Peter's Basilica in Rome and St. Albans Cathedral in England, which commemorate the martyrdom of Saint Peter (the first Pope) and Saint Alban (the first Christian martyr in Britain), respectively. The place, and therefore the church built there, was considered to have been sanctified (made holy) by what happened there. In modern times, the Catholic Church has continued this practice by placing in the altar of each church, when it is consecrated for use, a box (the sepulcrum) containing relics of a saint. The relics box is removed when the church is taken out of use as a church. In the Eastern Orthodox Church, the antimension on the altar serves a similar function. It is a cloth icon of Christ's body taken down from the cross, and typically has the relics of a saint sewn into it. In addition, it is signed by the parish's bishop, and represents his authorization and blessing for the Eucharist to be celebrated on that altar.

...
Wikipedia