Mechanical Terms Study Guide

Updated on Jul 15, 2011

Practice exercises for this study guide can be found at:

Mechanical Terms Practice Exercises

When a vehicle, an appliance, or anything complicated breaks down or needs repairs, it's never fun. And if you've ever accompanied a family member or friend who has had to take something in for repairs—or if you've done it yourself—you know how frustrating it can be to have a repair person rattle off a diagnosis and the solution when you don't understand a fifth of what's being said. Well, in today's lesson you'll learn some words that can help prevent that feeling of confusion and irritation. In fact, if you learn enough, you may find that not only can you carry on a conversation with repair people, but you can also learn to make a few suggestions and ask all of the right questions. Being savvy in this area might even save you a few bucks; you can figure out how to do your own repairs or know when you're being scammed and take your business elsewhere.

Please note that some of these words are technical and complicated terms, so just the most basic definition is given. Feel free to learn more about them on your own.


alignment     the proper adjustment of components for coordinated functioning; positioning something for proper performance

[You'll most likely hear this term in regard to your vehicle's tires, although your chiropractor might mention it as well. In both cases, it means the same thing.]

alloy     a mixture of metals, often a less costly metal mixed with a more valuable one through fusion

calipers     an instrument for measuring the internal or external dimensions of objects; in vehicles, it is part of the disc brake assembly that straddles the disc and presses the brake pads against it.

[Fun fact: this tool can also be used to measure body fat!]

camshaft     an engine shaft that has one or more integral cams attached, especially one that operates the valves in a vehicle's internal combustion engine

[And what's a cam? Glad you asked. It's a disk or cylinder designed so that when it's in motion, its parts create a rocking motion.]

coulomb     a unit of electrical charge

differential     in the automotive world, this refers to a drivetrain gear that connects two shafts or axles and allows one to move faster than the other

farad     a unit of electrical capacity

henry     a unit of inductance

hertz     a unit of frequency

ignition     the means of starting an engine; a spark that ignites the fuel-air mixture in an internal combustion engine

joule     a unit of energy

Kelvin     a unit of absolute temperature, named for an English physicist and mathematician

ohm     a unit of electrical resistance

pascal     a unit of pressure

pinion     a gear with a small number of teeth that typically engages with a rack, as in a vehicle's steering system

spoiler     a device or airfoil used for controlling lift and drag, such as an aircraft wing; in automotive lingo, a device for changing the airflow across a moving vehicle, such as a fin or blade mounted on the front or rear

strut     a long, rigid plank or board used to support a building

[Yes, it also means a pompous, arrogant way of walking.]

tachometer     a device for measuring rotation speed (revolutions per minute), often of a vehicle's crankshaft

[It's important to say it right too. It's not tack-o-meter. It's tack-OM-eter.]

tesla     a unit of magnetic flux density

torque     a rotating force, often referred to as the force generated by an internal combustion engine to turn a vehicle's driveshaft

Practice exercises for this study guide can be found at:

Mechanical Terms Practice Exercises

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