Named for Wilhelm Hofmeister, the Director of Design at BMW, the Hofmeister Kink refers to the following design quirk of BMW automobiles which is now a signature element of the company. Since its introduction in 1961 it has been included in all their cars.
It is the name for the small cutout of the rear side windows on the C-pillar of the car. Rather than having the rear side window extend all the way down as might be expected, it angles back toward the front of the car.
It appears that this has been imitated by other auto companies attempting to highlight and distinguish their "luxury" models.
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