Answer: because. And as it says "misnomer or not" which admits the idea we enter with: it's a bit cooked. BTW we're not laughing at you, we're just a bit bemuse

Answer: because. And as it says "misnomer or not" which admits the idea we enter with: it's a bit cooked. BTW we're not laughing at you, we're just a bit bemused, likewise why your 1st floor is what we call ground: we count from zero.