Terminology in the off-road community can be confusing at times for people who have not been around it for the majority of their lives. ATC, ATV, Quad, three-wheeler, six-wheeler, side-by-side, or SXS, utility terrain vehicle, or UTV, to some. It can not only be confusing, but it can also lead to deep philosophical questions.
Delving deeper into the whole situation, questions need to be answered: do you ride on it like a jockey or in it like a race car driver? Rarely do the worlds of cycle and vehicle collide as they do in the recreational off-road vehicle world.
Where did all this madness start?
The motorcycle has been around since the Daimler Reitwagen was invented in 1885 by Gottlieb Daimler and Wilhelm Maybach. This experimental, two-wheeled vehicle is widely recognized as the first internal combustion, petroleum-fueled motorcycle. Pinpointing the "first" purpose-built off-road motorcycle is a matter of historical debate, but a notable candidate emerged around 1914 with the Royal Enfield 3HP Model 180. This motorcycle, often cited for its military use in World War I, was designed to be sturdy and versatile for rough terrain.
To further muddy the waters, you could postulate that in 1885, even though there were limited macadam and even a few asphalt-paved roads, every motorcycle was an off-road machine. Ask yourself, then, why did companies see a need for something better?

In 1914, the Great War was raging across Europe. BSA stood for Birmingham Small Arms, and in those war years, they produced 1.5 million rifles, 145,000 Lewis machine guns, along with motorcycles. Before the war broke out, BSA had plans to produce an off-road motorcycle, the 4 1/4 HP Model H. It featured a 557cc single-cylinder engine. It answered the need for a purpose-built motorcycle due to the popularity of off-road motorcycle events rising in Europe and North America.
How about more contemporary information?
The first ATV was a six-wheeled contraption from a Canadian company called Recreatives Industries called the Jiger. It was a crazy-looking thing and achieved a small bit of fame when it was featured on the Saturday morning kids' show The Banana Splits as the "Banana Buggies."

The Jiger was its own conundrum because it was amphibious and could reach 4 mph in water, with ribbed tires serving as paddles. On land, a two-stroke engine transmitted power to the wheels via a continuously variable transmission, achieving a top speed of 25 miles per hour. Three were entered in the 1969 NORRA Baja 500, but to no one’s surprise, none finished.
It was after this that the three-letter all-terrain cycles were to become popular, starting with the ATC90 from Honda, otherwise dubbed a “three-wheeler”. Honda then followed with the Odyssey single-seater, a buggy of sorts equipped with a cage. Not long after that, the inherent safety issues with three wheels caught the attention of the United States Government, and they did what they do best: they killed the three-wheeler and, arguably, all the fun.

But it’s not a total loss. This inevitably left the door open for the four-wheeled cycle; after all, if three wheels were not safe enough, then four would surely be more stable, safer, and faster. Hence, the term ‘Quad’ was coined for what could also be called an ATV.
Let's look at the literal meaning of each
ATV: All-Terrain Vehicle capable of traveling over extreme off-road conditions. Quad: A four-wheeled vehicle capable of traveling over extreme off-road conditions. Samsies.
So, where are we on the whole Quad versus ATV thing? To quote Vizzini from the movie The Princess Bride, “Wait ‘til I get going! Now, where was I?”
We have explored the glorious roots of our beloved all-terrain machines and neatly filed them into categories. Yet, the Quad remains both an ATV and a type of ATC. But when you want to specify what kind of thing it is, since it has four wheels, it is decidedly hip and urban to use the Quad moniker.
Extrapolate that even further: if it has a stance on the ground of four items, can you call your pet dog a Quad? Your typical passenger car has four wheels, but a Honda Accord is most definitely not all-terrain. Yet, the family pooch is absolutely all-terrain, but less capable than a Quad. Therefore, while a dog is not a Quad, it is a quadruped. A different kind of quad.
Are you still with me?
It is a matter of dialect. In the South and Midwest, dinner is the midday meal, and supper is the evening meal. In many other places, the midday meal is lunch, and dinner is the evening meal. Just as in parts of the United States, a "Coke" is every carbonated beverage, while in others it is referred to as “pop” and in others “soda”. It is just about what you are used to.

We need a level of comfort with our linguistics; as humans are highly dependent on communication, we have this need to shorten words and phrases to get the point across quickly. Where Shakespeare would have Polonius say, “To thine own self be true, and it must follow, as the night the day, thou canst not then be false to any man,” today’s English would see someone say, “Be true to yourself, so you won’t be false to anyone else.”
Can a thing be two things at once? Look no further than the common umbrella, a repellent of water and a source of ultraviolet protection. So, if an ATV can be a Quad, a Quad can, in fact, be an ATV.