aisle
Τhe part of the naos of a church set off by the internal rows of piers or columns, namely by the structures supporting the roof.

apse
An arched srtucture or a semi-circular end of a wall. In byzantine architecture it means the semicircular, usually barrel-vaulted, niche at the east end of a basilica. The side aisles of a basilica may also end in an apse, but it is always in the central apse where the altar is placed. It was separated from the main church by a barrier, the templon, or the iconostasis. Its ground plan on the external side could be semicircular, rectangular or polygonal.

bema
The area at east end of the naos in Byzantine churches, containing the altar, also referred to as the presbetery or hierateion (sanctuary). In these area take place the Holy Eucharist.

corner bays
In a cross-in-square church, they are the four compartements between the arms of the cross, that make inscribe the central cross into a square. They were usually covered with cross-or domical vaults.

cross- (groin-) vault
A vault formed over square or rectangular spaces by the interpenetration of two barrel-vaults of equal hight and diameter. The lines of the intersection form a diagonal cross.

cross-domed basilica
Type of domed basilica. A church plan, whose core, enveloped on three sides by aisles and galleries with a transept, forms a cross. The core is surmounted by a dome in the centre.

cross-in-square church
Type of church in which four barrel-vaulted bays form a greek cross; the central square of their intersection is domed. The cross is inscribed into the square ground plan by means of four corner bays.

diakonikon
An auxiliary chamber of the church, also known in early years as skeuophylakion, which could be a separate building attached to the church. There were kept the sacred vessels but sometimes also the offerings of the faithful, the archive or library. In Byzantine churches the diakonikon becomes the sacristy to the south of the Bema, corresponding to the prothesis to the north, and forming along with them the triple sanctuary. It usually has an apse projecting to the east.

dome
A characteristic element of Byzantine architecture. The dome is a hemispherical vault on a circular wall (drum) usually pierced by windows. The domed church emerges in the Early Byzantine years and its various types gradually prevail, while they are expanded in the Balkans and in Russia.

drum of dome
Part of the church, semicircular or polygonal, on which rises an hemispheric dome

exonarthex (outer narthex)
The transverse vestibule or portico preceding the narthex of the church.

gallery
The upper level of a house where the women resided. In ecclesiastical architecture it is the corridor above the aisles and narthex of a church, from where women attended the Liturgy. Originally (in the Byzantine period) the gallery, having a special entrance, was used exclusively by the emperor and the members of the royal family.

Hodegetria
Iconographic type of the Virgin Mary. The Virgin is depicted standing, slightly turning to the right of the viewer, holding in her arms the infant Jesus. The type was named so after an allegedly thaumaturgic icon of the Virgin Mary kept in the monastery of Hodegoi in Constantinople.

katholikon
The main church in a monastic complex, heart of the monastic activity.

marble revetment
Τhe facing of a wall with slabs of marble

Medrese
The institution of medrese was the highest grade of the islamic education. The main courses which were taught to the young muslims were: reading, memorizing and interpreting the Koran, religious law, theology, philosophy etc.

narthex
A portico or a rectangular entrance-hall, parallel with the west end of an early Christian basilica or church.

opus sectile, the
Technique of floor or wall decoration. Thin pieces of polychrome marble are carved or joined so that a decorative motif could be depicted.

prothesis
Ιn ecclesiastical architecture, the sacristy to the north of the sanctuary. Usually it has an apse projecting to the east. It is the chamber where the eucharistic elements were prepared (Proskomide) before the Communion.

recessed brick technique
A masonry technique in which bands of wider and smaller bricks are alternated. The smaller bricks rows are slightly recessed and covered with mortar, thus creating an alternation of red (brick) and light-colored (mortar) surfaces.

templon or iconostasis
A structure separating the sanctuary from the main church. At first, it simply divided the nave from the presbytery, but later it became higher, with small columns and an epistyle. From the 11th century onwards, icons were placed between the templon columns and, somewhat later, icons were also placed above the epistyle, thus forming the iconostasis. The templon were originally from marble. Wooden iconostases appeared from the 13th century.

typikon
Foundation document of a monastery compiling the rules regarding its administrative organization and liturgic rituals, as well as the comportment inside a cenobitic monastery. The monastic typika could also include the biography (vita) of the monastery founder along with a catalogue of the movable or immovable property of the monastery. They constitute an important source for the study of the monastic life, while at the same time they shed light on many aspects of the Byzantine society. The liturgical typika were calendars with instructions for each day’s services, liturgical books with rules arranging the celebration rituals.