Antae: An extension of the sidewalls of a church beyond the gable walls forming rectangular pilasters (slightly projecting columns). These imitate the earlier wooden churches. The large wooden corner posts were used to support the roof.
Bailey: An earthen mound, adjacent to but lower than the motte, enclosed within a circular earthwork or fence. Most of the domestic buildings for the castle would be placed in the bailey. Baileys were either circular, oval or square in shape. Motte and Bailey castles were introduced to Ireland after the Norman invasion in 1169 AD. See also Motte.
Barbican: A structure or tower projecting out from a curtain wall at a gateway which protects the gateway into the castle and grounds. The purpose was to confine the enemy in a narrow passage and subject to attack while inside the barbican before they reached the gateway. They are also called a Death Trap.
Bartizan: A turret on the corner of a curtain wall tower that was one of the castle’s highest points thus serving as a sentry lookout.
Batter: A gradual widening of the wall at the base of a fortified castle or building that strengthens the wall. It is angled in such a manner to make dropped stones bounce away from the curtain wall and into the enemy.
Boss: A small ornamental projection, often round, used on stone crosses to simulate the look of wooden studs or rivets.
Burial Mound: An artificial elevation of earth or earth and stone usually built over the remains of the dead. Also known as tumulus or barrows A mound composed largely or entirely of stones is usually referred to as a cairn. Dated primarily from the Neolithic Period and Early Bronze Age (c. 4000 BC– 600 AD).
Cairn: Derived from the gaelic word 'carn' meaning a heap or pile of stones. Cairns may contain a tomb or chamber. Cairns over passage tombs may be dome-shaped; but there are other forms of cairns, such as those in trapezoidal or round shapes surrounding court tombs or wedge tombs. Dated primarily from the Neolithic Period and Early Bronze Age (c. 4000 BC– 600 AD).
Capital: Architectural stone at the top of a column or pilaster that supports an arch. The capital can be decoratively carved, and often projects outward as it rises to transition shape from a round column to a usually square topped supporting surface.
Cashel (Caiseal) and Cathair (Caher): Circular stone-walled enclosures of drystone construction -- the stone-walled equivalent of a rath. Usually found in rocky country with suitable stone for wall building, such as western Ireland, and rarely have a fosse or ditch . The term “cashel” is commonly used in the northwest while “cathair” is used in the west and southwest.
Chancel: The liturgical east end (right side in map view) of a church where the main altar is placed; usually reserved for the priest, other clergy and sometimes the choir. The chancel is typically raised somewhat above the level of the nave and may be separated from the nave by a chancel arch, rood screen (ornate screen, constructed of wood, stone or wrought iron), rail, or an open space.
Cinquefoil Window: A five-lobed shape found in window tracery.
Cist: A small (less than 1.5m square) box-shaped burial chamber made from stone slabs, with a slab capstone. They are excavated into the ground, and are often inserted into an existing cairn. Dated primarily from the Neolithic Period and Early Bronze Age (c. 4000 BC– 600 AD).
Clochaun: A drystone structure with a corbelled roof, usually taking the shape of a beehive. Concentrated in the southwest of Ireland, these buildings are often associated with monastic sites, such as Skellig Michael.
Cloisters: A covered walk with an open colonnade and courtyard on one side, and a wall on the other. Generally, but not always, located on the south side of the monastic church, connecting the church with the domestic parts of the establishment. Usually a quiet, secluded place for monks to walk.
Court Tomb: A type of megalithic tomb identifiable by a roofless court area with an entrance into a long, roofed, burial gallery, placed axially (usually aligned north to south) within a cairn retained by kerbstones. The gallery was usually divided into chambers with low corbelled roofs. There are single court, double court, centre court and full court tombs. Most are situated in the northern half of Ireland. Galleries were used for burial, mostly cremations. Dated between 4,000 and 3,500 BC.
Crannog: A small circular artificial island, 10 to 30 metres in diameter, built in lakes, rivers and estuaries, used as a settlement in early medieval times. They may have been used for defense at times of danger or as the island dwelling places of kings, lords, and prosperous farmers. They were most likely surrounded by a post or oak plank palisade, topped by a roundhouse. Some crannogs could be reached from the nearest shore by means of a causeway, but most were accessed by boat.
Cross-Inscribed Pillar: A slender, free-standing stone, square or roughly rectangular in shape, usually over 1m high, on the surface of which a cross has been inscribed or carved in relief. May have originally been erected by pagans but subsequently Christianized with the carvings. Found in ecclesiastical contexts or associated with holy wells and dated to the Early Medieval/Early Christian period (c. 500 - 1200 AD).
Cup and Ring Marks: Type of prehistoric carving (petroglyphs) consisting of a small concave depression pecked into a rock surface (the cup) and surrounded by concentric circles (rings) also etched into the stone. They occur on natural boulders and outcrops and also as an element of art on purposely worked megaliths, on standing stones and at stone circles, and incorporated into cairns and burial mounds. Dated to the Neolithic and Early Bronze ages (c. 3000 – 2000 BC).
Cup Marks: Type of prehistoric carving (petroglyphs) consisting of a small concave depression pecked into a rock surface. Can stand alone or with ring marks (see Cup and Ring Marks). Dated to the Neolithic and Early Bronze ages (c. 3000 – 2000 BC).
Cursing Stones: Smooth ovoid stones often found to fit perfectly in the depression of a particular bullaun stone. Also referred to as curing stones. The term cursing stone came from the tradition that if you wanted to put a curse on someone you turned the stone anti-clockwise, but be warned, if the curse wasn't justified it would rebound on the curser.
Curtain Wall: Outer wall surrounding medieval castles providing the first line of defense for the castle structures and grounds inside the wall. The walls were often connected by towers. Arrow slits and ramparts protected castle defenders on the wall from attackers. The curtain wall could be from 6 to 20 feet thick, and up to 45 feet high.
Ecclesiastical Enclosure: A large oval or roughly circular area, usually over 50m in diameter, defined by an earthen bank(s) and/or external drystone wall(s), enclosing an early medieval church or monastery and its associated areas of domestic and industrial activity. These date to the Early Medieval/Early Christian period (c 500 - 1200 AD).
Finial: An architectural ornament, typically carved in stone, used to emphasize the apex of a gable or pinnacle or the corner of a building or structure.
Fulacht Fiadh: Archeological sites consisting of a horseshoe-shaped pile of heat-fractured stone, rectangular water troughs lined with either slabs of stone or wood, and one or more hearths. It is believed they were used for cooking -- water was boiled in the water troughs by adding hot stones. They are found in every county in Ireland, with 2500 in Cork alone. They date from the Bronze Age (1400 – 700 BC) and may have still been in use until the 5th Century AD.
Gable: The end wall of a building, the top of which conforms to the shape of the building's roof.
Gallery: Composed of chambers in a tomb formed by large upright orthostat walls with horizontal roof slabs that may be corbelled. The chambers are separated by jambs. Between jambs there is often a low sill stone.
Garderobe: A small chamber that served as the toilet in a castle, which discharged to a cess pit, moat or directly onto the street outside. Clothes were hung in the garderobe because it was believed that the rising steam from the urine killed the lice and fleas.
Hill Fort: A fortified (enclosed by an earth or stone bank) settlement located on a hilltop for defensive advantage. Contains one or more ramparts made of earth, stone and/or wood that follow the contours of the natural slope, often with an external ditch. Appeared at the end of the late Bronze Age and beginning of the early Iron Age (c. 1100-1300 BC).
Holy Well: A spring or other small body of water that was likely a sacred Pagan site which became Christianized. They commonly bear a saint's name and are reputed to possess miraculous healing properties. They may have their origins in prehistory but are associated with devotions from the medieval period (c. 500 - 1500 AD) onwards.
Jambs: Two large upright stones placed opposite each other, creating an entrance or dividing galleries into chambers.

Kerbstone: One of a series of large stones encircling a burial mound or cairn to form a retaining wall/Kerb. Generally associated with passage tombs, but also found surrounding court tombs and wedge tombs.
Kist: Stone-sided burial chamber, generally built above ground and covered by a cairn. They are usually box shaped but other shapes are known. Dated primarily from the Neolithic Period and Early Bronze Age (c. 4000 BC– 600 AD).
Knights Hospitallers: A military and religious order founded as the Knights of the Order of the Hospital of St John of Jerusalem in the 11th century.
Label Stops: A piece of scupture found at the end of decorative moulding.
Lavabo: A place found in monasteries where monks washed their hands before entering the church. In ecclesiastical terms, it refers both to the basin in which the monk or priest washes his hands and the ritual itself. In secular usage it refers to a handbasin.
Leacht: A small square or rectangular dry stone structure associated with Irish Early Christian monastic sites. Their precise function is unclear but they may have been erected as burial markers, reliquaries, or to serve as an alter or station of the cross.
Lintel: A stone slab placed horizontally spanning the top of an opening, usually to support a wall or roof.
Machicolation: An opening in the floor of a projecting parapet or fighting platform above the entrance to a defensive building such as a castle through which stones, liquids or other missiles could be dropped on attackers.

Megalith: A large stone which has been used to construct a structure or monument, either alone or together with other stones. The word 'megalith' comes from the Greek megas meaning great and lithos meaning stone.

Megalithic Tomb: Aboveground burial chamber, built of large stone slabs (megaliths) and originally covered with earth or other, smaller stones. The structures were built mostly during the Neolithic period into the Bronze Age (c 4800 – 500 BC) by Neolithic farming communities. There are a variety of megalithic tombs such as court tombs, portal tombs, passage tombs and wedge tombs.
Motte: An enditched mound, usually topped with a wooden or stone fortified structure known as a keep (central tower on a castle) . The earth for the mound would be taken from a ditch, dug around the motte. The height of mottes varies greatly, the majority being under 5m, and they are predominantly rounded in plan. Some mottes may have been constructed from Raths. Motte and Bailey castles were introduced to Ireland after the Norman invasion in 1169 AD. See also Bailey.
Murder hole: Similar to a machicolation only it is inside the castle front door where a small room or passageway confines attackers. The hole in the ceiling of this room is called a murder hole because liquids, stones and other projectiles can be dropped down onto the attackers.
Nave: The central axial section of the liturgical western arm (left side in map view)of a church, where the public attends services.
Ogham : A written language used mainly in Ireland. Ogham script consists of groups of 1 to 5 parallel lines cut either above, below or through a baseline, usually the vertical edge of a standing stone, to represent the sounds of the primitive Irish language. Current understanding is that the names of the main twenty letters in Ogham are related to the names of 20 trees sacred to the celts. AKA The Celtic Tree Alphabet.
Ogham Stone: Standing Stones bearing inscriptions in the ancient Ogham alphabet. It reads from the left side of the stone from the base up. The inscription gives a person's name (usually male), immediate antecedent/s or tribal ancestor. Chiefly confined to the south of Ireland, the stones may have functioned as memorials, grave markers or territorial markers and date from the 4th century AD.
Order: One of a series of recessed arches and supports on a Romanesque doorway, chancel arch, etc. A doorway or arch may be described by the number of orders.
Orthostat: A large stone set upright used in constructing the walls of chambers and passages in many kinds of megalithic tombs during the Neolithic Period (c. 4000 BC– 600 AD). The orthostats directly or indirectly support the roof structure.
Piscina: A stone basin, with a drain, in a church or sacristy, used to dispose of water used in ceremonial ablutions and other sacraments by returning the water and the particles it washes away directly to the earth.
Plinth: The projecting block supporting a column, pedestal, statue or monument. Also used in Romanesque architecture as projecting courses supporting a wall; the upper edge is usually moulded. It is believed to be the transition between a structure and the ground.
Portal Stones: Two megalithic orthostats that form an entrance to a tomb or stone circle. In recumbent stone circles they are usually the tallest stones, with the height of adjacent stones gradually decreasing with distance from the portal stones.
Promontory Fort: A defensive enclosure created by constructing one or more lines of ramparts on a raised block of land like a cliff or across a neck of land in order to defend or restrict access to a spur or promontory in a coastal area. These date to the Late Bronze to Iron Age (c. 700 BC - AD 400).
Rampart: A protected fighting platform for defenders. Built behind an earthen embankment or as a walkway on a stone wall top with a parapet such that the front/exterior face of the stone wall is higher than the rear walkway. Most ramparts are associated with external ditches that provide an extra component of the defensive structure. Common amongst the late Bronze Age and early Iron Age (c 1000 – 600 BC).
Rath: A fortified raised-earth ringfort enclosing a Medieval/Early Christian (c. 500 - 1200 AD) farmstead. The term rath sometimes applies to the enclosing bank, while the term lios can refer to the open space within. The rath may have one or more fosse or ditch(es) from where the earth to construct the raised circular rath was taken, and may have more than one bank. Rath profiles are sometimes indistinguishable from mottes if no evidence of the bailey has survived.
Recumbent Stone Circle: A stone circle containing one recumbent stone - a large stone laid on its longest side–flanked by the two largest of the standing stones with adjacent stone heights sloping downward from this location. The midpoint of the recumbent stone, often called the altar stone, usually aligned with the sunset during the midwinter solstice. Recumbent stone circles date to 3000 BC.
Ringfort: A roughly circular drystone wall or earthen bank enclosing a Medieval/Early Christian (c. 500 - 1200 AD) farmstead, designed to provide shelter and security for a family and its livestock. Sometimes more than one bank or wall is present, giving rise to the labels uni-vallate, bi-vallate etc. The complexity and number of the banks or walls served as an indicator of the occupier´s status. Ringforts are further classified into ráths (Earthen) and cashels (Stone).
Rock Art: Man-made motifs that are pecked out or “carved” on natural stone. Synonymous with petroglyphs. Often associated with a Bronze Age date (c. 2400-500 BC), but may have origins in the Neolithic (c. 4000-2400 BC). Possible purpose includes marking boundaries or routeways and recording seasonal events.
Roofbox: Open space above the entrance to a passage tomb which allows the rays of the sun at sunrise to penetrate the passage and illuminate the central chamber.
Sarcophagus: A coffin carved or cut from stone . Usually bearing sculpture and/or inscriptions, and often displayed as a monument.
Sill Stone: A low or recumbent stone placed between two jambs in a gallery or at the entrance to a tomb or gallery.
Souterrain: An underground structure consisting of one or more chambers connected by narrow passages or creepways, usually constructed of drystone-walling with a lintelled roof over the passages and a corbelled roof over the chambers. They are common in ringforts of the Early Christian period (c. 500 - 1200 AD) as a defensive feature and/or for storage of valuables and perishable foods.
Standing Stone: Solitary stones deliberately set vertically in the ground and usually oriented on a north-east-south-west axis, although other orientations do occur. They vary in height and date from the Bronze and Iron Ages (c. 2400 BC - AD 500), with some associated with early medieval ecclesiastical and burial contexts (c. 500-1200 AD). The stones possibly functioned as prehistoric burial markers, commemorative monuments, indicators of routeways, alignments or boundaries.
Stele: An upright stone or wooden slab, with an inscribed or sculptured surface, erected for funerals or commemorative purposes, most usually decorated with the names and titles of the deceased or living. It can also be used as territorial markers to delineate land ownership.
Stone Circle: An approximately circular setting of upright standing stones with their broad sides facing inwards, towards the centre. Circles often have similarities within a geographical region. Many have solar, lunar or star alignments marking seasonal events (oriented on sight lines for the rising or setting of the sun or moon for the equinox and solstice) and are generally regarded as ceremonial sites. Stone circles have their origin in the Neolithic (c. 4000-2400 BC) though they are primarily of early to middle Bronze Age (c. 2400-1500 BC).
Stone Pair: Two upright megalithic standing stones. Usually the stones are totally different in size; one may be pointed or rounded and the other flattened or grooved suggesting male and female relationships
Stone Row: Three or more upright megalithic standing stones aligned in a straight line and placed at set intervals. Often found in association with cairns and stone circles, and the terminals often have the largest stones. They may be religious, aligned on various solar or lunar events, or set to form a ceremonial processional avenue. They date to the late Neolithic or Bronze Age (c. 2400-500 BC). Also called Stone Alignments.
Transcept: In a cruciform-shaped church, the transcept is the part that crosses the main church, separating the nave from the chancel.
Tumulus: An artificial elevation of earth or earth and stone usually built over the remains of the dead. Also known as burial mounds or barrows. A tumulus composed largely or entirely of stones is usually referred to as a cairn. Dated primarily from the Neolithic Period and Early Bronze Age (c. 4000 BC– 600 AD).
Tympanum: An architectural element located over a doorway often with decorative figures carved in it. Usually refers to the stone between the lintel and an arch above it.