The orientation of a building refers to the direction in which it is constructed and laid out, taking account of its planned purpose and ease of use for its occupants, its relation to the path of the sun and other aspects of its environment.[1] Within Christian church architecture, orientation is an arrangement by which the point of main interest in the interior is towards the east (Latin: oriens). The east end is where the altar is placed, often within an apse. The façade and main entrance are accordingly at the west end.
The opposite arrangement, in which the church is entered from the east and the sanctuary is at the other end, is called occidentation.[2][3][4][5]
Since the eighth century most churches are oriented. Hence, even in the many churches where the altar end is not actually to the east, terms such as "east end", "west door", "north aisle" are commonly used as if the church were oriented, treating the altar end as the liturgical east.[6]