Strictly speaking a "mid-engine " car has the engine in front of the rear axle but behind the passenger compartment. But strictlier speaking it's only strictly speaking because that's the way the only 'mid-engine' cars in actual production are laid out. Most of them are two passenger or front seat only sports or at least "sports-type" cars. There are 'experimental,' prototype,concept, and special purpose vehicles with the engine in a more central location, between the front and back seats ( actually more like two separate passenger compartments), some with the engine to one side or the other, so if they ever went into production we could have a right-front- mid-engine car or a mid-mid-engine. But maybe not, things can get complicated.In a rear engine car, like the old Volks 'Bug', the engine is over, or even behind the rear axle. In a front engine car the engine is over or in front of the front axle. In the early 60's Chevrolet sold a Corvair van with an air cooled engine mounted under the cargo compartment behind the front seat. That was the most 'mid' of any arrangement I can think of. But it wasn't called 'mid-engine' it was a 'Forward Control' vehicle. The front seat was over, mostly in front of the front axle. I drove one of those for a couple of years in the 70's, sitting out there in front of the axle gave a great view but felt like riding a yo-yo. Around the same time the Big 3 came out with full size vans with the axle in front of most of the engine and the passenger seat moved back where it was supposed to be, the engine extended into the passenger compartment, I think Ford was the first and the most extreme with most of the engine actually between the front seats. They weren't called 'mid-engine' or even 'Tween the seats', they were 'Cab Forward' apparently the engine was where it should be for a 'front engine' but the seats had been moved forward to straddle it, but not so far as to become a 'Forward Control.' So if any of the bizarre proto-types go into production, or more likely as "hybreds' and 'alternative' become more common, with electric motors on each axle or even each wheel, or mounted here or there, who knows what they will be called. Or by whom, "official' names given by manufacturers have a way of being replaced by common usage names. That "Forward Control" Corvair became known as a "Bouncing Bobtail. " Maybe soon we'll all be driving 'toward the left of the right rear mid of the left forward engine cab sidewards reverse control vertically mounted engine pick-up/limosenes'.

This is a tricky semantic question. Mid-engine vehicles are TECHNICALLY any vehicle that places the engine between the front and rear axles. However many people argue that the term applies strictly to those vehicles that place the engine behind the passenger compartment but in front of the rear axle, possibly because most mid-engine cars are laid out thusly. There are cars with "Mid-front" engines that have the engine moved rearward for better weight distribution. This provides many of the weight distribution advantages of mid-rear, but allows for a back seat. For a little more info, check TypeR's answer on the effects of engine placement on handling/performance here : http://www.answerbag.com/a_view.php/18872

You are right in your definition of a mid-engine car. Mid-engine cars are probably more common than people realize. I drove a Renault 5 (marketed in the US as Le Car) for many years and it had a front-mid engine layout. The engine was oriented longitudinally, rather than transversely, with the gearbox / differential unit in front of the engine. Some panel truck designs have also used a front-mid layout with rear-wheel drive. Rear-mid designs are much less common, because the engine intrudes more noticeably into the interior space. I recall some urban buses I rode several decades ago that had a rear-mid configuration. Most buses now have their engines behind the rear axle.

Yes and no. The mid-engined car was designed to improve handling. An engine outside of the axles with either force the car to go straight ahead (understeer) or make the bend tighter than it's supposed to do (oversteer). What you mostly will see is the engine in the middle of the car, but more towards the rear wheels for maximum traction. Put the engine more to the front and you will find yourself with the problem where to place the driver. A car that actually comes fairly close is a typical BMW. You will see that the overhang up front is very short, leaving the engine BEHIND the front wheels. They did that with a very specific reason.