Trade Glossary — Learn the Language of the Trades

The base unit of electrical current. One amp equals one coulomb of charge flowing past a point per second.

A worker learning a skilled trade under the supervision of experienced journeypersons, typically through a combination of on-the-job training and classroom instruction.

An electrical discharge between an electrode and the workpiece that generates intense heat (up to 10,000°F) to melt and fuse metals.

An unintended electrical discharge that can cause fires. AFCI breakers detect these and cut power to prevent ignition.

An off-road dump truck with a hinge between the cab and dump body, providing excellent maneuverability on rough terrain.

A device installed on water lines to prevent contaminated water from flowing backward into the clean water supply.

The deposited filler metal left on the workpiece after a welding pass. A good bead is uniform in width and height.

The arrangement of drill holes for explosives in mining or quarrying operations.

A detailed technical drawing that shows the design, dimensions, and specifications of a building or structure. Used by all trades on a construction project.

Blowout Preventer — a large valve at the top of a well that can be closed to prevent uncontrolled release of oil or gas.

British Thermal Unit — the standard measure of heating or cooling capacity. One BTU raises 1 pound of water by 1°F.

A formal document authorizing a modification to the original scope, cost, or timeline of a construction contract.

A safety device that automatically interrupts electrical flow when current exceeds a safe level, protecting wiring from overheating and fire.

An access point in a drainage system that allows plumbers to clear blockages using a snake or hydro-jetter.

A set of regulations and standards (e.g. National Building Code, NEC, Plumbing Code) that govern how construction and installation work must be performed.

Equipment used to compress soil, gravel, or asphalt to increase density and stability.

The heart of an air conditioning system that pressurizes refrigerant gas, enabling the heat-exchange cycle that produces cooling.

A tube or channel used to protect and route electrical wiring, made from metal (EMT, rigid) or PVC.

Traditional metal piping used for water supply lines, valued for durability and resistance to corrosion.

Certified Welding Inspector — an AWS credential for professionals who inspect and ensure weld quality meets code requirements.

A valve or plate inside ductwork that regulates or redirects airflow to different zones of a building.

The tower-like structure over a well that provides the height necessary for drilling operations.

The refining of petroleum crude oil and processing of raw natural gas, as well as marketing and distribution of products.

A crawler-type tractor equipped with a large metal blade used to push large quantities of soil, sand, or rubble.

A large excavating machine that casts a bucket attached to cables to remove overburden in surface mining.

The system of metal or flexible channels that distribute heated or cooled air throughout a building from the HVAC unit.

A heavy construction machine with a boom, dipper, bucket, and cab on a rotating platform for digging trenches, holes, and foundations.

The consumable material added to a weld joint to fill the gap between two pieces of base metal. Must match or exceed base metal strength.

A chemical cleaning agent that prevents oxidation during welding. Found as a coating on stick electrodes or as a core in flux-cored wire.

Flux-Cored Arc Welding — similar to MIG but uses a tubular wire filled with flux, allowing outdoor use without external shielding gas.

The on-site supervisor responsible for directing a crew of workers and ensuring tasks are completed safely and on schedule.

Hydraulic fracturing — a well stimulation technique involving injecting high-pressure fluid into rock formations to create fractures.

The main contractor responsible for overall coordination of a construction project, hiring and managing subcontractors.

Ground Fault Circuit Interrupter — a device that shuts off power when it detects current leaking to ground, preventing electrocution. Required near water sources.

A machine with a long blade used to create a flat surface during grading, typically used in road construction.

Slang for a new, inexperienced worker in the trades, particularly in oil and gas or construction.

Hydrogen Sulfide — a toxic, flammable gas commonly found in oil and gas operations that can be lethal at high concentrations.

The structure at the top of a mine shaft that supports the hoisting equipment used to raise ore and lower workers.

A system that transfers heat between indoors and outdoors, providing both heating and cooling. More energy-efficient than traditional furnaces in moderate climates.

A work rotation period, typically 2–3 weeks on followed by 1–2 weeks off.

A skilled tradesperson who has completed an apprenticeship program and is fully qualified to work independently in their trade.

Job Safety Analysis — a procedure that helps identify potential hazards of specific tasks and determine the best way to perform the job safely.

An enclosed box used to connect and protect electrical wire splices and connections within a wiring system.

Living Out Allowance — a daily stipend paid to workers who must travel and live away from home for work.

A heavy equipment machine used to move or load materials such as soil, rock, sand, or demolition debris into trucks.

Lockout/Tagout — safety procedures used to ensure dangerous machines are properly shut off and not able to be started up again before maintenance work is completed.

The transportation, storage, and wholesale marketing of crude oil, natural gas, and refined products.

Gas Metal Arc Welding — a semi-automatic process that feeds a continuous solid wire electrode through a gun, shielded by an inert gas.

Drilling fluid circulated through the wellbore to cool the drill bit, carry rock cuttings, and maintain pressure.

National Electrical Code — the U.S. standard for safe electrical design, installation, and inspection. Updated every three years.

A surface mining technique where minerals are extracted from an open pit or borrow, creating a large terraced hole.

Rock containing valuable minerals in sufficient concentration to make extraction economically viable.

Occupational Safety and Health Administration — the U.S. federal agency responsible for enforcing workplace safety regulations.

Cross-linked polyethylene tubing used for water supply lines. Flexible, freeze-resistant, and easier to install than copper.

Personal Protective Equipment — safety gear including hard hats, safety glasses, steel-toe boots, gloves, and high-visibility clothing.

A thorough check of equipment before operation to identify any mechanical issues or safety hazards.

A list of remaining tasks or deficiencies that must be completed or corrected before a construction project is considered finished.

Polyvinyl chloride pipe used primarily for drain, waste, and vent (DWV) systems in residential and commercial plumbing.

The process of restoring land that has been mined to its natural or economically usable state.

A Canadian interprovincial certification that allows tradespeople to work in any province or territory without additional testing.

A chemical compound (e.g. R-410A, R-32) that absorbs and releases heat as it circulates through an HVAC system's evaporator and condenser.

Request for Information — a formal written request from a contractor to the designer or owner seeking clarification on drawings or specifications.

A brand name for non-metallic sheathed (NM) electrical cable commonly used in residential wiring for branch circuits.

The phase of plumbing installation where pipes and fittings are installed inside walls and floors before fixtures are attached.

A worker on a drilling rig responsible for the physical labor of drilling operations.

Seasonal Energy Efficiency Ratio — a rating that measures air conditioning efficiency. Higher SEER = lower energy cost. Minimum 14 SEER required in most regions.

Fine crystalline silica particles generated during mining and drilling that can cause serious lung disease (silicosis) if inhaled.

The glassy byproduct that forms on top of a weld from flux. Must be chipped off between passes to prevent inclusions.

A metal alloy melted to join copper pipes and fittings. Lead-free solder is required for potable water systems.

The most common HVAC setup with an outdoor unit (condenser/compressor) and an indoor unit (evaporator/air handler) connected by refrigerant lines.

A person who guides equipment operators during backing or blind-spot maneuvers, ensuring safety around other workers and obstacles.

Shielded Metal Arc Welding — the most versatile process using a consumable flux-coated electrode. Works outdoors and on dirty/rusty metal.

A specialized contractor hired by the general contractor to perform a specific portion of work such as electrical, plumbing, or HVAC.

An assistant or helper, typically working alongside equipment operators or truck drivers to assist with various tasks.

The waste material left over after the process of separating valuable minerals from ore.

A control device that monitors temperature and signals the HVAC system to turn on or off to maintain a set temperature.

An electrical power system using three alternating currents offset by 120°, common in commercial and industrial settings for heavy loads.

Gas Tungsten Arc Welding — a precise manual process using a non-consumable tungsten electrode and optional filler rod, shielded by argon gas.

A measure of an air conditioner's cooling capacity. One ton equals 12,000 BTUs per hour of cooling power.

A short safety meeting held at the worksite before starting work to discuss specific hazards and safety procedures for the day's tasks.

A U-shaped pipe fitting that holds water to create a seal, preventing sewer gases from entering a building through drains.

The lower part of tracked equipment including tracks, rollers, idlers, and sprockets — the most expensive component to maintain.

Mining operations conducted beneath the earth's surface through shafts and tunnels.

The exploration and production sector of oil and gas, including drilling wells and extracting crude oil and natural gas.

A vertical pipe that extends through the roof to allow air into the drainage system, maintaining proper pressure for waste flow.

The system of providing fresh air to underground mines and removing contaminated or heated air.

The electrical pressure that pushes current through a circuit. Residential systems are typically 120V/240V; commercial can be 208V/480V.

An angled edge preparation on metal pieces to allow full penetration of the weld into the joint.

Workplace Hazardous Materials Information System — Canada's national hazard communication standard for workplace chemicals.

American Wire Gauge — a measurement of wire diameter. Lower numbers mean thicker wire capable of carrying more current.