Do 49 focus points mean the camera will focus on 49 different areas at the same time?

I’ve read a lot but could not find a clear explanation.
As I understand, a lens can only focus physically on one point since the focus depends on the physical position of the lens vis-a-vis the sensor. So what is the purpose of these 49 focus points my camera has? Does the camera take an average of the points to determine the final single focus? In that case, I don’t see why 49 points would be any better than 5 or 10 points.