I’ve always called a cyclorama an infinity wall. It is a white background that curves as the bottom so you can’t see where the floor ends and the wall begins. There is no line there.
Here’s a great video on how to build one. This is no simple project. They really build not only the curve, but also the floor.
Oh and the video itself is really well made and fits how we do things at my studio. Though photographer and model does not endorse the use of power tools while only wearing lingerie for safety reasons.