There are two different types of lenses based on whether they can or cannot zoom. The term prime lens is used for lenses which have a fixed focal length. I.e., they cannot zoom. These lenses are less complicated to operate thanks to the absence of one ring.
The term focal length has been explained elsewhere on this website. For the term zoom lenses please refer to this section.
Since prime lenses have a fixed focal length manufacturers concentrate on the optics of the lens. Manufacturing processes are geared towards image sharpness, quality, and contrast.
Apart from these, there are other prime lenses too like the portrait photographer’s favorites the 85mm and the 105mm as well as the 135mm. These are many others.