Sentence:  Trade-in values for <WSD>station wagons</WSD> have shown a marked improvement since the introduction of the all-steel body. In fact, a <WSD>station wagon</WSD> buyer need not worry about his investment′s depreciating any more than he would have to if he bought a four-door sedan. 
Meaning of the word marked with <WSD> tags:  A body style for cars in which the roof is extended rearward to produce an enclosed area in the position and serving the function of the boot (trunk) of a sedan / saloon.