Quote Originally Posted by Mike52
FWIW, this is the way it was explained to me many years ago. It's a 'convertible' if the top can go Down and the side windows can go Up, making it capable of being converted from a 'closed car' to an 'open car'. If it doesn't have side windows, it's considered a 'roadster'.
This is my definition too. Mine is a roadster- no side glass.
I'll try & call again Monday or send an E-mail to nail down their definition.

Lots of interesting facts here! Glad I asked the question.