Gable Area 
The triangular surface wall that runs between the sloping ends of a ridge roof, on the gable end of the building, and the top wall plate. 

Gable Decoration 
A triangular decorative feature, such as over a door or window. 

Gable Dormer 
Dormer that is built into a gable roof. 

Gable End 
Triangular wall enclosed by the sloping ends of a ridged roof and the top wall plate. The entire section, including wall, roof and space enclosed is referred to in that manner. 

Gable End Brace 
The brace that runs from the roof ridge board at the gable end to the top wall plate at the gable end and adds stability to the ridge board. 

Gable End Stud 
Stud which goes upward from the end wall of the horizontal gable top wall plate to the end rafter. 

Gable Roof 
Roof design where all of the rafters are cut to the same length and joined in the center to form a peak, with two sides of the roof sloping down from that peak. 

Gable Vent 
Screened vent or louver, which allow hot air to leave the area in the gable, ends of the roof. 

Gag 
1. Metal block, used with in a vise, which is sized and shaped to give the needed contours to the piece of metal that is bending or shaping. 
2. Clamp that is used to prevent the safety valve on a boiler from opening. This is used when the boiler is hydrostatically pressure tested. 

Gag Rule 
Contractual provision prohibiting buyers from publicizing complaints about the builder. 

Gain 
1. Increase in money or property values over the carrying value of the property, received on the sale or exchange of that property. 
2. A mortise, which is a recessed slot or a notch. 
3. The cut made into the doorjamb to install the hinge plate to be set flush with the surface. 

Galilee 
Porch located at the entrance of a church. 

Gallery 
1. A long narrow balcony on the exterior of a building. 
2. A long narrow corridor or room. 
3. An exterior covered walkway, which is open on one side and/or has supporting pillars. 
4. A platform or projecting upper floor attached to the back wall or sides of a church, theater, etc. 
5. A porch or veranda. 

Gallon 
Measurement of liquid capacity, which is equal to 4 quarts or 231 cubic inches. 

Gallons Per Minute (GPM) 
Measurement of volumes of intermittently flowing fluids. 

Galvanic Action 
Flow of electrons which occurs when two dissimilar metals come into contract in the presence of moisture which is capable of carrying electric currents, resulting in the corrosion of the more active metal, which is lower on the galvanic scale, without damage to the more passive metal. 

Galvanic Scale 
A grading or ranking of metals, which show their susceptibility to galvanic action. 

Galvanize 
Protective coating added to inhibit corrosion or oxidation of metal, by hot dipping the metal in zinc or electroplating it. 

Galvanized Iron 
Zinc coated iron. 

Galvanized Steel 
Zinc coated steel - the coating is used to make the steel waterproof. To be completely waterproof, the steel must be hot-dipped galvanized. 

Galvanized Steel Pipe 
Steel pipe that has been coated, both internally and externally, with zinc to provide protection from corrosion. 

Galvanometer 
Laboratory instrument that detects and measures small electric currents. Galvanoscope Instrument that measures and determines the direction of electric current. 

Gambrel Roof 
Roof style with two different slopes from the ridge to the eaves, resembling that of barn. The lower slope is steeper than the upper flatter slope. 

Gang 
1. A set of tools, machines, etc. designed or arranged to work together. 
2. A group of workers directed by a foreman. 
3. A group of people associated together in some way. 

Gang Box 
Also called a handy box, this small, steel or plastic box is used to mount outlets or electrical switches in walls or for joining conduit or cable. 

Gang Drilling 
Stacking up a group of panels so that the holes that are drilled are identically placed in all of the panels. 

Gang Mandrel 
Steel shank that holds more than one tool or several pieces of work to turn simultaneously on a lathe. A nut threaded on the end of the shank hold the pieces in place. 

Gang Milling 
Using multiple heads for milling or shaping more than one piece at a time. 

Gang Operations 
Working on several identical items simultaneously. 

Gang Saw 
Power saw equipped with multiple blades to make several parallel cuts at once. 

Gangway 
Walkway to temporarily provide access to a construction site. 

Gantry Crane 
Bridge crane, which is mounted on rails that are supported on a trestle-like set of, braced legs.