(v.) The act of depreciating, is lowering the value of an asset with a calculable value. This mostly refers to the value for old items falling as the demand for them wanes.
There is a lot of depreciation to be considered on the prices of cars where the manufacturer constantly changes the look. 50's, 60's and 70's Mercedes-Benz were almost unchanged, right down to the starting point for change- the headlights. This means that such collectors items are worth more (when inflation is added) then current Mercedes will be at that age. Since BMW likes to change appearance more often, thier cars depreciate more.