Originally Posted by Frank_Zuccarini
To my knowledge, no one has satisfactorily explained why that is so.
It's pretty clear with the pan off. The dipstick comes in at an angle. The "bottom" side of the dipstick gets more oil on it than the "top" side.
The correct orientation is with the oil symbol "right side up" when you're standing at the nose of the car... this will always have the letters on the "top" side of the dipstick that gets less oil, and this is the side to read.