OK terminology is like a holy war to some but in order of complexity you have


Speedster - usually a 2 seater, erector set top if it has one, side curtains if present.


Roadster - may have a folding top but disappears under the tonneau usually a two seater


Drop Head Coupe (UK) aka Cabriolet (Eur) folding top that is visible or under a fabric cover when down. Can be two or four passenger


Convertible Coupe (US) single row of seats,


Convertible (US) may have multiple rows of seats


- all of the above have fabric roofs


Reatractible, Retracting-roof Hardtop , or Hardtop Convertible (US) -metal folding roof - 1957 Ford Sunliner was first production car. Modern ones do not have the FA.