"Is a Prelude a true sports car?" Well, forget the "true" bit, it's not even remotely close to being a sports car! One of the commentators goes on to confuse the issue even more by naming sports cars that are in fact, by pretty much any definition I've ever seen, supercars. Another gets GTs a bit confused, pitching them too close to the racing-derived cars they may or may not be based on. But that's all based on my understanding of the terms and it's that that's not a shared understanding where the waters get muddied.
Typically, I would see a sports car as a roadster, definitely RWD and a GT as a more comfortable continent-crosser in that original Gran Turismo sense, albeit still with prodigious power available. That leaves room for plenty of shades of grey in between though - my favourite car, for instance, the Ferrari 250 GT SWB was not open but was a racer for the road (in fact, most of the customer cars were racers rather than road cars) so does that qualify as a sports car?
As far as the watches go, we can take a usage approach. I could agree that an Autavia has a bit much case and bezel to be a sports watch, but I know that Siffert, Hill, Bell etc all used them for timing their laps and I reckon that makes it de facto a sports watch. I then have to admit the Chronosplit into the sports watch fold, because Gilles Villeneuve used one of those in the same way. And I suspect if we looked long and hard enough, we could find professional racers who used Silverstones, Jaramas, Veronas etc etc too.
As human beings, we like to classify and compartmentalise, from Linnaeus classifying species to Mendeleyev organising elements to the standard model of particle physics but without that shared understanding and vocabulary, it's a tough job sometimes. Even now, getting on for 3 centuries after Linnaeus' work, naturalists still argue over what constitutes a species - I doubt the sports watch discussion will last that long and I wonder if, 3 centuries from now, if historians will be debating what a car was, let alone whether it was sports or not!
