Civil Engineering Terms and Definitions

Civil Engineering Terms and Definitions

Some of the basic Civil Engineering Terms and Definitions are listed below,

Arcade : A series of arches with their supporting columns or piers.

Arris : The meeting of two surfaces producing an external angle.

Base: Base is immediately above plinth. A building having no plinth, immediately above footings.

Basement or Basement Storey or Cellar : Part of a building (usually a storey) below ground level,

Bat: Part of a brick.

Baiter : The slope away from you of a wall or timber piece, etc.

Bay : The space between two piers, columns or projections.

Bay window: A window projecting outward from a wall and reaching up to the ground.

Bevel: Any inclination of two surfaces other than 90 deg. (either greater or less),

Blocking Course : A course of stones (or only one stone) placed on the top of a course to add to its appearance and also to prevent the cornice from overturning.

Bressummer : Joist embedded in concrete; beam over verandah posts on which purlins of sloping roofs rest. Also means a beam which carries a wall.

Brick core : Brickwork filled in between the top of a lintel and the soffit of a relieving arch.

Brick flogging: Brickwork filled in between wooden posts or studs (for making a wall).

Bull’s eye : A circular or oval opening in a wall.

Buttress: A projection of masonry built into the front of the wall to strengthen it for lateral stability against thrust from an arch, roof, or wind pressure.

Flying Buttress : A detached buttress or pier of masonry at some distance from a wall, and connected therewith by an arch or portion of an arch, so as to discharge the thrust of roof or vault, on some strong point.

Chamfer: To cut off, in a small degree, the angle or arris formed by two faces, usually at an angle of 45 deg.

Chase : A recess made inside of a wall to accommodate pipes or electric Wiring, etc.

Composite Building : A building of which part is masonry and part is either open or framed ; or a building of which part is open building and part is framed building. .

Coping: The capping or covering placed upon the exposed top of a wall (or parapet), usually of stone, to throw off and prevent the rain-water soaking in to it.

Corbel: One or more courses of brick projecting from a wall like a cornice), generally to form a support for wall plates, etc. A brick should not project more than 1/4 beyond the lower course.

Counterfort: Is a projection of masonry built into the back of the wall.

Cowl: A hood shaped top for a chimney; a ventilating top of a sewage pipe. .

Cross Wall: An internal weight bearing wall built into another wall to the full height thereof.

Dormer Window : A small vertical window built in a sloping roof.

Dowel: A pin or peg let into two pieces of stone or wood for joining them ; a cramp iron.

Drip : Part of a cornice or projecting sill etc., which has a projection beyond other parts for throwing off rain-water.

Efflorescence: The formation of a whitish loose powder or crust, on the surface of brick walls. .

Extrados: The outer surface of an arch.

Frog: Is a small recess on the top surface of a brick, made while moulding, usually embossed with the initials of the contractor. It forms a key for the mortar and also reduces the weight of the brick.

Gable : The entire end wall of a building. (The term is generally used for the triangular end wall of a sloping roof.)

Haunch : That part of an arch lying midway between the springing and the crown.

Herring-bone work: Masonry work (generally in floors) in which the bricks are laid slanting in opposite directions. .

Hydroscopic: A substance that attracts water from the air.

Intrados: The inner surface of an arch.

Lambs : The two sides of doors, windows or other openings between the back of a  and, the chowkat or frame. The portions of the openings outside the frame are called Reveals.

Joggle : A dowel or stub tennon joint by means of which one piece of stone or timber is fitted to another.

Keystone : The uppermost or central voussoir of an arch.

King closer: A brick cut lengthwise so that one end is nearly half the width of the other, They are used in the construction of jambs.

Lobby : An open space surrounding a range of chambers, or seats in a theatre ; a small hall or waiting room.

Mantel: The facing and shelf (usually ornamental) above a fire place.

Mastic : A preparation of bitumen used for water proofing and damp proofing, etc.

Mat finish : A term applied to surface finishing (generally painting) which is free from gloss or polish (not shining),

Mezzanine floor : An additional (low storey) floor, gallery or balcony erected between the floor and ceiling of any storey.

Mosaic : Small pieces of stones, glass,. etc. (generally of different colours) laid in cement mortar to form artistic patterns for flooring and dados, etc.

Mullion : An upright (piece) in any framing ; a division piece between the sash of a frame.

Oriel Window: An upper storey window projecting outward from a wall (and which does not reach up to the ground, as distinguished from a bay-window).

Party Wall: A wall erected on a line between adjoining property owners and used in common.

Pedestal: A base or support, as for a column or statue, and generally of a bigger size.

Pilaster : A right-angled column or projection from a pier or wall; a square pillar made generally to support a concentrated load.

Pillar : A detached vertical support to some structure; a solid portion of a wall between window openings and other voids.

Plinth : The portion of the external wall between the level of the street and the level of the floor first above the street.

Queen closer: A brick cut lengthwise into two so that each piece is half as wide as the full brick.

Quoin brick : A brick forming a corner in brickwork ; it has one end and one side exposed to view.

Recs: A depth in the thickness of a wall.

Refractory materials : The term “refractory” is applied to various heat resisting materials such as, lire-bricks, furnace linings.

Reveal: A vertical side of a window or door opening from the face of the wall to the frame. (See lambs).

Skew-back: That (inclined) part of a pier or abutment from which an arch springs.

Sleeper Walls : Low walls erected at intervals between the main walls to provide intermediate supports to the lowest floor.

Soup header :A brick header not extending the full length of a brick into a wall, usually half a brick.

Soffit : The lower horizontal face of anything ; the under face of an arch where its thickness is seen.

Spall:  Bat or broken brick; stone chips,

Spandrel or Spandril: The space between the top of a masonry arch and the roof, beam or carriageway, etc.

Spandrel Wall : A wall built upon the extrados of an arch up to the top level of the roof or beam, etc.

Splay: An oblique surface (bevel or chamfered), as of the jambs of a doorway or Window ; of which one side makes an oblique angle with the other.

Springing line : A line of intersection between the intrados and the supports of an arch.

Spring points: The points from which the curve of an arch springs.

Springer: The voussoir placed next to the skew-back in an arch.

Squint Bricks: Bricks used for forming acute or obtuse corners in brick masonry.

Striking : The releasing or lowering of centering of arches or lintels.

String course :. A horizontal (usually ornamental) course projecting along the face of a building (usually introduced at every floor level or under Windows or below parapets) for imparting architectural appearance to the structure and also keeping off the rain water.

Throating:  Term used for making a channel or groove on the under side of string courses copings, cornices or sun-shades, etc., to prevent rain water from running inside towards the walls.

Underpinning : The process of supporting the. existing structure for renewing or repairing the lower Walls or foundations.

Vault : An arched masonry structure (with series of arches).

Veneered Wall: In a wall in which the facing material is merely attached to and nor properly bonded into the backing.

Voussoir : The wedge shaped structure component of a stone arch.

Weathering: Action of sun and rain on structures or soils.

The Civil Engineering terms and definitions will be updated regularly.

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Plaster of Paris

Plaster of Paris

Plaster of Paris is calcined gypsum. Mixed with ordinary lime it is used for repairing holes and cracks in wooden or plastered surfaces, and for making moulds and ornamental works. When mixed with water its swells slightly and sets rapidly.


Gypsum is natural calcium sulphate and occurs as a soft stone which is from white to dark in colour. It is used mainly in the manufacture of cement.

Barium Plaster is employed as finishing coat to X-ray room walls, It consists of 1 part cement, 2 parts of fine and 2 parts of coarse barium sulphate powder. Thickness varies from 6 mm to 12mm.



Kankar is extensively used for producing hydraulic lime. The nodules should have a blue grey fracture, free of any sand grains or mud sticking to them, and broken to pass a 12 mm gauge before being calcined.

Kankar is a nodular variety of limestone which is of spongy nature, found in almost all parts of India containing some quantity of clayey and silicious matter. It is found either in layers or blocks, or in separate nodules. The block form occurs as solid deposits at various depths, and the nodular variety is generally found scattered on the surface or in small thicknesses about a metre or so below the surface in the low lying portions of the catchments of nallas and rivulets. The nodules are of sizes varying from 10 mm to 100 mm. Nodular kankar is superior to block kankar but is not available in large quantities. Shining or glittering particles in a fresh fracture indicate presence of sand. The proportions of clay and sand can be determined by dissolving the sample in powdered. form in dilute hydrochloric acid and determining the residue left. “Bichwa” kankar as known in the Punjab and U.P. in India is considered to be the best.


Terracotta is a kind of earthenware which is generally used as a substitute for stone in the ornamental parts of buildings. It is made like clay products burnt at very high temperature; usually contains : 8 parts sifted dry clay, 3 parts crushed pottery, 2 parts white sand, I part ground glass. Porous terracotta is made by adding saw dust or ground cork, and is very light but weak structurally. It can be sawed and nailed very easily.

Terracotta is vitrified on the surface and made into various colours and patrons. Hollow blocks are made for walling etc. It is fire-proof and is unaffected by the atmosphere and can be jointed with cement mortar.