What exactly should be the bare minumum for a car?

A seat, a single steering wheel and a shaft, an engine and 4 wheels with no suspension. Should you could this as a car? Why, or why not?

I want practical definitions. Attack helicopters are not cars practically even though we can define anything to the point of anything.

When do cars become NOT cars?

As ever, one can trace the word car back to the Latin language.

Essentially meaning a wheeled device for carrying stuff.

So a wheelbarrow will do.

Eh, what about if we change our scope to "automotive transportation device"? What is the bare minimum for that?

I am trying to draw cars on paper and after 40 minutes I have essentially created...a 4-wheeled wheelbarrow. That is not automotive.

So a car needs a cup holder. Understood. All F1 cars except maybe Kimi's are not cars.

Well if you were in the building trade, you would find that motorised wheelbarrows are popular.

Nonetheless in terms of an "ATD".

4 wheels preferably, with pneumatic tyres.

A motor, preferably electric these days.

A steering device.

Definitely a reliable braking system.

And some sort of cover to protect both the motor and the passenger/s from inclement weather.

Oh, and a seat/s.

Suspension is optional, but certainly benefits the experience, as does a lot of other modern ATD equipment. 

You clearly fail to understand that cup holders are the greatest thing since sliced bread.

Do you actually believe in that there will be fewer cars in 20 years than now?

What monster eats their bread sliced. I just compress my loaf of bread into a 5x5x5(centimeters, lol) cube of wheat substance then eat it in one bite, maybe two or three if I don't have any water with me.

As of cup holders, I haven't got a license in driving but I am pretty sure that most cars have a general hold for anything, right next to the shift stick, and I have heard numerous Americans, southerners or not, putting cheeseburgers there with a side of dipping sauce, well, more times than they put coke. Other than that, I simply don't know of an explicit cup holder in the average car.

Will there be fewer cars twenty years from now.

All depends upon the  affordability of new ATD technology.

And then there's the strong possibility of WW3 to consider.

4-wheeled vehicle. That's literally it, and all industries and sporting events actually go by the amount of wheels a vehicle has.

A small truck is more of a car than Peel P50. Why?

At least culturally speaking, trucks aren't cars. 

Trucks(some) are 4-wheeled.

true, but they also serve other purposes

You are arguing against your own definition doc. You are saying a 4-wheeled truck is a car because it has 4 wheels then saying it is not because they have a different purpose. What is the practical definition then.

Not so much a belief as a fervent appeal to common sense

4-wheeled vehicle specifically used for transportation

Ah fine.(pulls away with Liebherr dump truck, obviously a car)

...." This bamboo Ajiro concept bicycle rethinks both our means of transportation and the ways we manufacture our vehicles. Designed by Monash University student Alexander Vittouris, the Ajiro utilizes a production process that removes emissions instead of releasing them into the Earth’s atmosphere. That’s because the bamboo structure of this vehicle is grown straight out of the ground into a preformed mold. Vittouris envisions fields of bamboo gardens growing these human powered bicycles, which need only small modifications once mature to hit the streets. "...

When do we get the first fungus grown in mold bicyle?

That thing is 3 wheeled and is more an electric scooter with a canopy than an actual car. It is literally more this than a car.

Scooters have two wheels.  Cars have three or more wheels as do some motorcycles, tho in both cases three is not typical of either one.

Airplanes use three wheels and very common, and they are long way from a scooter or a car, but closer to a car.

A herbal tricycle scooter thing is closer to a car than a plane, and actually way too far from either one of them to be considered them. So, at this point, is considering what is or isn't a car by the number of wheels even a good choice here?

Norman Foster recontruction of dymaxion{s} cars{3-in-one }

3 wheeled dymaxion meets 3 wheeled jet https://www.youtube.com/watch?v=YTt2L4nL0tE

You never miss a pothole with this design ;--(

You can easily haul stuff in an SUV or back in the day station wagon. The difference between a truck and a car is like the difference between a river and a creek. It's just a designation of size.

Its like the differrence between a normal bomb and an atomic bomb, this is likened to the differrence between normal consciousness and intense psychedelic consciousness.

Electric uni-cylclist just needs proper back-pack  with cup holder hangs off chest in front.

Two wheel scooter goes back to my childhood of this mo-ped scooter, with platform for feet, pedals and huge cargo space under big seat. Just needs coffee cup holder.

Then along came the 3-wheeled Big Wheel. The hot rod of tricylces.

Fullers later designs --doing more with less--- for Dymaxion had front wheel steering, but you still will not miss a pot hole. He could not raise the money for these later designs to be protoyped.

Four wheels hit less pot holes.  Less coffee spilt in our laps. :--))

One might be tempted to suggest that the three wheel pothole argument is not logical.

If one is not paying attention, potholes will inevitably be encountered....So 4 chances instead of 3.

In fact if one is not paying attention, all sorts of things might be encountered.

Also, potholes tend not to be in the centre of a lane, but at the edges of the lane where most wear occurs.

One might be tempted to suggest that the three wheel pothole argument is not logical.

Once you take a 3-wheele car or cycle on the road, I think you better understand why it occurs more with 3-wheels.

Ergo more split coffee from try to evade the pot holes and spare the tires the impact.

 A 3 wheeled tricycle is different from taking a tire off a car, and only one of them is actually a car. Guess which one?

I also mention unicycle  with a coffee cup holder. One wheel is minimal mode of transportation. Two is next then three.

Car is a mode of transportation on highways, countrys, back roads to get us from point a to b.

Some  Jeeps { cars } designed with no roof coverings ---not a covertibale either--- in world war 2--- and today still such not open to weather jeeps are still designed.