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ampere the unit of measure for electric current. Also abbreviated amp. Many power tool motors are sized according to the amperage their motor draws.

anchor a device that can be driven or set in concrete, masonry, or other material to provide a place to attach a bolt. There are several types of anchors.

apprentice a person who is being trained to work in the building trades. Apprentices attend classes and work under the supervision of a skilled craftsman.
area the space inside a shape

ball bearing a style of bearing in which moving parts roll on steel balls.


base of a triangle the side opposite the corner from which the height is measured. This can be any side of the triangle.

blade (rafter square) the longer arm of a square.


body language unwritten, unspoken message communicated by the way we hold our body or the expressions on our face.

box nail has a thin shank like a finishing nail, but a flat head like a common nail. Usually coated to prevent loosening.
brad a very short nail with a small head, used to fasten thin parts.

cap screw a small bolt, usually with a hexagonal head


carriage bolt a large bolt for use in wood. Has a smooth oval head and a section of square shank right below the head.


centerline a line used to indicate the center axis of an object.

chuck the part of a drill that holds the drill bit.
chuck key a special tool used to tighten a drill chuck.
circle a shape in which every point on the perimeter is the same distance from a center point.
class A fire a fire that involves ordinary materials like paper, cardboard, and wood. Class A fires can be extinguished with water.
class B fire a fire that involves flammable liquids. Class B fires are extinguished with either dry chemicals or CO2 (carbon dioxide).
class C fire an electrical fire. Class C fires are extinguished with CO2 (carbon dioxide).
clinching bending the protruding part of a nail over to make a permanent fastening.
combination blade a saw blade that can be used for ripping and crosscutting.
common nail the most common type of nail. Has a heavy, smooth shank and a flat head.
competent person one who is capable of identifying existing and predictable workplace hazards that are unsanitary, hazardous, or dangerous to employees and who has the authorization to take corrective measures to eliminate them.
conductor a material that allows electricity to flow.
contractor the person who owns the construction business. Contractors enter into contracts with customers to do specified construction work. Contractors hire workers or other ubcontractors to complete the contracted work.
corporation a form of business ownership in which people who are not involved in operating the business own shares of the company. The company is operated by a board of directors.
craft see skilled trades.
cube a three-dimensional shape in which height, width, and depth are all equal.
cutting-plane line a line used to show where a section view is taken from and in what direction it is viewed.

decimal fraction a number representing a quantity of less than 1 and expressed according to the decimal number system.


decimal point the dot used to indicate the separation between whole numbers and decimal fractions.


deck screw similar to a drywall screw except it is more corrosion-resistant.

denominator the number on the bottom of a common fraction.
developer the person or company that buys undeveloped land and works with architects and contractors to develop it into more valuable property.
difference the result of subtraction.
dimension line a line used to indicate the size of an object or feature.
double-insulated a style of electric tool construction that shields the user from the electric parts of the tool.
drywall screw a light-gauge screw with a Phillips or square-driven head, used for fastening drywall to framing. Drywall screws are not as strong or as corrosion-resistant as other screws.
duplex nails a common nail with two heads, so that one can be driven tight and the other is still exposed for removal.

elevation a view of an object as seen from the side and showing the height of the object.


ethics the discipline dealing with what is good and bad and with moral duty and obligation.


extension line a line used to indicate the extent of a dimension line.


4:1 rule for ladders the rule that stipulates that ladders should be 1 foot away from the vertical surface against which they are placed for every 4 feet in height.


factor a number that when multiplied by another factor produces another number.


finishing nail has a thin shank and small head that can be driven beneath the surface of the wood.

fire triangle consists of heat, fuel, and oxygen (the three sides of the triangle); the three elements must be present for a fire to burn.
floor plan shows the size and locations of rooms and most features in the rooms or on the specified level of the building.
foundation plan shows the layout and size of the foundation.
fraction bar the horizontal line in a common fraction.

grade line a line on a drawing that shows the surface level of the ground.


ground (electrical) a conducting body that serves as the common return path for an electric circuit. A ground typically has zero potential. The earth may also be used as a ground.

ground fault circuit interrupter (GFCI) a protective device that opens the electric circuit when an imbalance in the amount of current flow between the conductors is sensed.


hash mark a short line on a drawing, used to indicate the end of a dimension line.


headers the framing across the top of a window or door opening.


height of a triangle the length of a line drawn perpendicular to one side of a triangle and extending to the opposite corner.

hidden line a dashed line used to show edges that are hidden from normal view.
horseplay practical jokes and playful activity that are inappropriate on a construction site.
hypotenuse the side of a right triangle that is opposite the right angle.

isometric drawing a drawing with horizontal lines drawn at an angle of 30°.

journeyman a skilled craft worker who has completed an apprenticeship or otherwise proved his or her ability in the trade.

kerf the cut made by a saw.




labels user instructions found on most construction products. The product label contains valuable information.


laborer an unskilled or semiskilled worker on a construction site.


lag screw a large wood screw with either a square or hexagonal head.

lay the direction in which the strands are wound around the core of a wire rope. Also the distance along a rope in which a strand makes a complete turn around the core.

leader a line used to associate a label with an object. Leaders usually have arrowheads.

level parallel to the earth’s surface.
longitudinal section a section view showing what would be seen at an imaginary cut through the length of the building or part.

lowest common denominator the smallest denominator that can be used to express all of the common fractions in a set.


Material Safety Data Sheet (MSDS)gives complete information about the product and what to do in the event of exposure. An MSDS is required to be available for any substance that might be harmful.

metric system a system of measurement based on 10 (often called the SI system).


minuend the number from which another number is to be subtracted.

mixed number a number made up of a whole number plus a common fraction.

nominal dimensions the dimensions of a product before allowances or adjustments are made. The sizes of many construction materials are identified by their nominal dimensions. For example, nominal dimensions of lumber are the dimensions of lumber before it is dried and planed or the
dimensions of masonry units including the mortar joints.


numerator the number on the top of a common fraction.




object line a heavy solid line used to show the outline and/or shape of an object.


oblique drawing a drawing with one surface shown on the plane of the paper and the adjoining surface at an angle.


orienting showing the relationship of one drawing to another.

orthographic projection a style of drawing in which separate sides of an object are shown as if projected against the inside of a glass box.
OSHA refers both to the state and federal Occupational Safety and Health Administration and also to state administrations. OSHA also stands for the Occupational Safety and Health Act, which is administered by the Occupational Safety and Health Administration. OSHA generally refers to the laws that are intended to keep workers safe.

partnership a form of business in which more than one person shares the ownership and operating duties for a company.


penny size (abbreviated d) refers to the size of a nail. Nails are measured by an old system that used the number of pennies to purchase 100 nails of that size. The higher the penny size, the
longer the nail.


perimeter the distance around the outside of a shape.

personal protective equipment (PPE) any safety equipment you wear to protect yourself from safety hazards.

pitch a measurement of the number of threads in 1 inch of a screw or bolt.

pitch (saw) the coarseness of the teeth of a saw. Pitch is measured in points per inch.

plan view a view of an object as seen from directly above.


plate the uppermost framing member in the wall.

plumb perfectly perpendicular to the earth’s surface.
plunge cut a cut made by plunging the saw in the middle of the work piece instead of cutting in from an outside edge.

pneumatic tools tools powered by compressed air.

polarized plug an electric plug having one prong wider than the other so that it can only be plugged into the receptacle one way.

portable ladder a ladder that can easily be picked up and carried to another location.


profession an occupation that requires more than four years of college and a license to practice.

pump jack a device that attaches to a vertical pole and can be pumped up and down the pole. Pump jacks are used to support planks on which workers stand.
Pythagorean theorem a mathematical law that says the sum of the squares of the sides of a right triangle are equal to the square of the hypotenuse.



rated capacity the amount of weight the manufacturer has specified for the maximum load on a sling


reciprocate move back and forth in a straight line. Some saw blades reciprocate.


rectangle a shape with four 90° corners and with opposite sides of equal length.


reference marks callouts on plans and elevations that indicate where details or sections of important features have been drawn.

reversing switch a switch found on most electric drills that allows the user to reverse the direction of the drill.

right angle a 90° angle.

Right to Know rule the OSHA rule that says that every worker has a right to know about any substances on the job that might be harmful to humans.

right triangle a triangle with a 90° angle.

roller bearing a style of bearing in which moving parts roll on small steel rollers.

scaffolds temporary work platforms.


scale the amount of reduction or enlargement of an object that is drawn other than the actual size. Also a device used to measure objects that are drawn proportionately smaller or larger.


screw gauge a number representing the thickness of a screw. The higher the gauge, the thicker the screw.


section a view of an object as though the object had been cut in half.

semiskilled labor workers with very limited training or skills in the construction trades.
sheet metal screw usually a self-tapping screw, used for fastening sheet metal.

shoe as used on power tools, the part of the tool that rests on the work piece.

sides of a right triangle the two sides next to the right angle. The hypotenuse is not referred to as a side.

site plan also called plot plan. Shows the size of the building site and the location of the building, driveways, sidewalks, and utilities on the site.

Skil saw a term sometimes used to mean a portable circular saw. The first portable circular saw was made by Skil, and so some people call all portable circular saws Skil saws.

skilled trades the building trades— carpenters, electricians, plumbers, painters, and so on. These occupations require training and skill. The skilled trades are often referred to as the crafts.

sleeve bearing a style of bearing in which moving parts ride on a smooth metal sleeve or tube.

sole proprietorship a business whose owner and operator are the same person.

solid a three-dimensional shape. Spheres and cubes are two types of solids.

square a shape with four 90° corners and four equal-length sides. Square also refers to the result of multiplying a number by itself.

stove bolt a small bolt with a round or flat head and fitted for a screwdriver.

subcontractor a contractor who is performing work for another contractor.

subtrahend a number that is to be subtracted from another number.
sum the result of addition.



tag line a light line attached to a load to control it by hand.>

Tapcon a concrete screw.

target rod a graduated pole used with a builder’s level to measure elevation.

technicians technicians provide a link between the skilled trades and the professions by using mathematics, computer skills, specialized equipment, and knowledge of construction.

thimble a steel insert in the eye of a wire rope sling to prevent kinking and wear.

toenailing driving a nail at an angle into the face of one piece to hold it to another piece. Toenailing usually requires at least one nail on each side of the piece being toenailed.

tongue (rafter square) the shorter arm of a square.


transverse section a section view showing what would be seen at an imaginary cut across the building or part.

triangle a shape formed by three sides.
tripod three-legged stand for holding a builder’s level or a transit.

typical section a section view that shows typical construction. Variations of this detail would not be typical and would require special detail drawings.


U.S. customary system the system of measurements used in the United States based on inches, feet, quarts, gallons, pounds, and so on.


unskilled labor workers with no specific training in the construction trades. This term also applies to work that does not require training.




values what we believe is right and wrong.

voltage the electrical pressure that causes current to flow, measured in volts (sometimes bbreviated as V). Voltage is sometimes called electromotive force (EMF) because it is the force that causes electrons to move. Voltage also represents the difference of potential, or potential difference, in a circuit.

volume the space enclosed by a threedimensional figure.


wire rope clip a clamping device used to hold two pieces of wire rope to form an eye.

wire rope a rope made from strands of wire wrapped around a core in a particular way. Wire rope is sometimes incorrectly called cable.


work practices the things a worker does and how he or she works—these practices have a lot to do with safety.


working conditions the things in the work environment that affect your work.