The phrase "frameless side" means something that does not have a border or outer edge. It refers to the absence of a frame or any kind of surrounding structure. Full definition
The proportions are clearly those of a coupé: the long bonnet, narrow - look windows with frameless side windows, and dynamic roof sloping back towards the rear. (thetorquereport.com)
The proportions are clearly those of a coupé: the long bonnet, narrow - look windows with frameless side windows, and dynamic roof sloping back towards the rear create a basic stance with which it looks ready for the off. (thetorquereport.com)
Combined with frameless side glass the overall result is a coupe - like profile exaggerating the car's length and appearing to be lower than the tape measure indicates. (autofile.ca)