Architectural and Engineering Glossary



Abbr. for gauge or gage.


Igneous rock similar to diorite, predominantly composed of ferromagnetic minerals with crystals visible to the eye; has the same mineral composition as basalt.


A cylindrical wicker or metal basket that is filled with stones; used in the construction of foundations.


1.A  vertical  surface  commonly  situated at the end of a building, usually adjoining a pitched roof; its shape depends on the type of roof and parapet, although most often it is triangular; often extends from the level of the cornice up to the ridge of the roof. If the gable   is on the façade rather than the back end, the building is said to be front gabled. 2.A similar end that is not triangular in shape; for example,   a gambrel end (US). For definitions and illustrations for particular types see bell gable, broken gable, clipped gable, corbie gable, corbiestep gable, cross gable, crowfooted gable, crowstep gable, curvilinear gable, docked gable, Dutch gable, end gable, façade gable, Flemish gable, front gabled, hanging gable, intersecting gable, multicurved gable, parapet gable, segmental gable, side gable, stepped gable, straight line gable, truncated gable, tumbled in gable, wall gable.

Gable Coping

The protective cap covering a gable wall that projects above the line of the roof finish.

Gable Elbow

A single step at the base of a straight line gable.

Gable Finish

The molding or cornice around a gable end, usually on the eaves of a building. 

Gable Front

A façade that is front gabled. gable front and wing plan The plan of a house having its long side perpendicular to the street and having a gable on the end facing the street; a wing is added at the rear of the house.

Gable On Hip Roof

A hipped roof in which the hips are not carried all the way to the ridge; instead, each end roof surface turns vertically near the top so as to form a small gable that is perpendicular to the ridge.

Gable Ornamentation

Any type of decorative element on the face of a gable, such as spindle  work, near the apex of a gable.

Gable Post

 A short post located at the peak of a gable into which the bargeboards are fixed.

Gable Roof

A roof having a single slope on each side of a central ridge; usually with a gable at one or at both ends of the roof.

Gable Shoulder

Projecting brickwork or masonry which supports the foot of a gable.

Gable Springer

skew block, skew butt A kneeler, 1 (esp. a projecting one) which is at the foot of a gable or the like.

Gable Vent

A louvered opening in the gable of a roof; used to exhaust air from an attic.

Gable Wall

A wall which is crowned by a gable.

Gabled Tower

A tower finished with a gable on two sides or on all sides, instead of terminating in a spire, or the like.


A small ornamental gable.

Gaboon, Okoume

A wood resembling African mahogany but softer and lighter in weight.

Gadroon, Godroon

An ornament composed chiefly of ovoid or more elongated bosses regularly repeated, side by side.

Gag Process

The process of bending structural shapes in a gag press.


 In carpentry, a groove or notch in  one piece into which another piece is fitted.


A decorative pedestal, esp. one tapered downward and square in section. Also see estípite


On drawings, abbr. for “gallon.”


In Spanish Colonial architecture, an open, covered porch, usually arcaded, either facing a patio or the street.


A gallery or porch. In French Vernacular architecture of Louisiana, a roofed porch, usually open sided, often extending across the entire front, across the front and one or more sides, or completely around the building on the upper level.

Galerie House,

gallery house In French Vernacular architecture, a farmhouse or plantation house evolved by French speaking settlers in the Louisiana Territory; usually has a roofed galerie either across the façade or across the façade and one or both sides of the house; typically has gabled dormers with windows. Also see Cajun cottage and Creole house.


A narthex or chapel at the entrance of a church; often used for worship.

Galilee Porch

A galilee that has direct communication with the exterior of a church; can be considered as a vestibule to the principal part of the church.


Unusual growth of plant tissues; a result of the introduction of a foreign substance such as a chemical or fungus, or a result of mechanical injury.


1.A long, covered area acting as a corridor inside or on the exterior of a building, or between buildings.2.An elevated area,  interior or exterior, e.g., minstrel gallery, music gallery, roof gallery.3.An elevated section of the seating area of an auditorium, esp. the uppermost such space.4.In buildings for public worship, a similar space, sometimes set apart for special uses.5.A service passageway within a building, or linking a building underground to exterior supplies or exits. Some service galleries also serve sightseers, e.g., the lighting gallery in the base of the dome at St. Peter’s, Rome.6.A long, narrow room for special activities like target practice, etc.7.A room, often top-lit,  used  for the display of art works.8.A building serving such  art  needs.9.See long gallery.10.Any raised working platform at the side or rear of a theater stagehouse.11.An  arcade, 2.12.(Brit.) A device, attached to a lampholder, for supporting a reflector, shade, etc.

Gallery Apartment House

An apartment house having external passageways which provide entry to individual apartments on each floor.

Gallery Grave

A prehistoric burial place consisting of a long stone lined gallery without a tomb chamber, and covered by an artificial mound.


A stone chip or spall.

Galleting, Garreting

1.The insertion of stone chips into the joints of rough masonry to reduce the amount of mortar required,to wedge larger stones in position,or to add detail to the appearance.2.Pieces of tile used to provide a suitable bed for ridge tile or hip tile. 3.The insertion of small pieces of flint or colored stone in soft mortar; serves as a decorative element.

Gallows Bracket

A triangularly shaped bracket fixed to a wall,such as one to support shelving.


On drawings, abbr. for “galvanize.” 

Galvanic Anode

See sacrificial anode. 

Galvanic Corrosion

An electrochemical action which takes place when dissimilar metals are in contact in the presence of an electrolyte,resulting in corrosion.


To coat steel or iron with zinc,as,for example,by immersing it in a bath of molten zinc.

Galvanized Iron

Sheet metal of iron coated with zinc to prevent rusting;used extensively for flashings, roof gutters,gravel stops,flexible metal roofing, etc.

Galvanized Pipe

A steel pipe or wrought iron pipe,of standard dimensions,which has been galvanized by coating it with a thin layer of zinc. 


The process of coating steel or iron with zinc by immersing it in a bath of molten zinc.

Gambrel End

An end wall of a structure having a gambrel roof.

Gambrel Roof, Gambrel

1.(US) A roof which has two pitches on each side;in Great Britain called a mansard roof.2.(Brit.) A roof  which has a small gable near the ridge on one end; the part of the roof below the gable is inclined.Also see Dutch gambrel roof,English gambrel roof,Flemish gambrel roof, New England gambrel roof,Swedish gambrel roof.

Game Room

A room used primarily for recreation,often downstairs in a dwelling.

Gamma Protein

Protein obtained from soya beans;used as a thickener in water base paints.

Gang Boarding

See cat ladder.

Gang Nail

A registered trademark of Gang Nail Systems, Inc. A type of timber connector consisting of a metal plate having a series of spikes at right angles to it.

Gang Saw

A powered assemblage of parallel reciprocating saw blades;used to cut a quarry block into slabs;generally utilizes a loose abrasive material with water,or diamond or tungsten carbide blade inserts,to effect the cutting.