What is a converging lens?

A converging lens is a lens curved on both sides with its center thicker than the edges. It is also commonly known as a convex lens.

Converging lenses are named as such due to the fact that light rays coming out of the lens converge at some point to form an image. The point at which the light rays meet is called the focal point. The image is located and formed when the light rays pass through the lens and converge at the focal point. Converging lenses are used in refracting telescopes, similar to the type Galileo could have used.