When is a car a 'supercar?'

A number of times this year we've had supercar rallies around the coast, they are largely Ferrari, Lambo and Porsche, but what is it that makes them super; brand, performance, price?
I suspect if I turned up in the coop or the Alfa I'd get laughed at, but some Alfas would probably meet the criteria.
If it's performance, some tuned coops, Nissans and Fords would give them a run for their money.
If it's price one of the most common vehicles around here is the Range Rover which can cost £100k, but not that exclusive or 'super' to my mind.
If it's Brand does that mean all cars from that manufacturer, Porsche and Ferrari have had a few duds, there are some 'supercar' Mercs but most aren't.

Mid-engined
Less than 4 seats
Minimum of 8 cylinders

Impractical
Rare

When you can't afford it

When even if you can afford it you still can’t get it

Bit of a coincidence this, but I pick up a V8 R8 tomorrow.

It's mid-engined, less than 4 seats, has 8 cylinders, impractical(ish) but it isn't rare.

As cars get smaller engines these days, we might have to include 6 cylinder (even the old Jag XK220 was a V6).

But usually they are 8 or more. Some have electric boost but that's not exclusive to supercars.
Dare I say some might be fully electric?
Generally 2 seater. Didn't the McLaren F1 have 3?
Generally designed to be driven on a track (if required) a bit like Range Rover are designed to be driven off road except most aren't.
I'm not sure mid engine is critical. Plenty of rear and front engine supercar, though some might be considered GT cars.
Expensive and exclusive
Essential: must be Italian.

Good luck with the R8. Must say I do like them.

Interested in a private plate for the R8? I bought the plate but then never bought an R8

PM me if interested.