Ok I have a 1974 L82 convertable. I was told it is a roadster. What actually defines a roadster?

Ok I have a 1974 L82 convertable. I was told it is a roadster. What actually defines a roadster? People just refer to a convertible as being a roadster so all convertibles are considered roadsters. And no , I didn't spell convertible wrong. For some odd reason car dealers have always spelled it with an i instead of an a .