[TeMPOraL]

> though that probably is stretching the definition of a door a little bit...

It is, but then so is the stupid "3-door" / "5-door" / etc. car classification, which is really 2-door / 4-door / etc. with the trunk being counted as additional door for some reason.

[garaetjjte]

I think it makes sense for hatchbacks, where there's no real trunk/passenger cabin separation.

[vel0city]

The trunk is considered a door when it opens into the main cabin instead of a separate compartment.