Some would say a sports car can only have two seats, an independent rear suspension, and a few other tidbits. Here is a photo of classic Brit sports cars.

If you
really want to get technical, per racing definition from 50 years ago, a sports car has no top. An enclosed car is, at most, a GT. An enclosed car with a back seat is a sedan.
I once had a TR3A like this one.

This is a '60; mine was a '59. I can't tell the difference between the two years--there may not have been any. About 1/3 of mine was painted primer rather than black, and I had bolt-on stamped steel wheels rather than wires w/knock-off hubs. It was freezing cold in the winter and overheated in the summer, and I never got it straightened out. The overdrive didn't work.
I drove it from Fort Hood, TX, to Fort Rucker, AL, for the Apache course. It overheated several times, so I made terrible time. It started running on two cylinders at night in Mississippi. I stopped at a truck stop and used some sort of wire to repair the carburetor linkage, and got back on the road. I arrived at Rucker at about 8:00 a.m., and class had started at 7:30. I checked in at the BOQ, changed into uniform, drove it to the right building, and started class.
Driving back to Fort Hood, I got into a cold, driving rain in Louisiana. First time I had driven it in a serious rainstorm. Water was coming in everywhere, including up through the floor. And, of course, the heater didn't work. I wrapped a blanket around my legs and kept driving. I stopped at my sister's place in Dallas about 2 a.m. starting to suffer from hypothermia.
Oh, but it was great for short trips on pleasant spring or fall days!
Oh, I forgot about George Lucas, the Prince of Darkness. British cars back then all had Lucas electrical systems.
When I got that car, a T-shirt came with it. It had a cartoon of a leaking refrigerator and asked: "Why do British drink warm beer?"
The answer: "Lucas refrigerators."