what are rocky planets and why are these called rocky planets?

Rocky planets, also known as terrestrial planets, are celestial bodies composed primarily of solid rock and metal. They have a well-defined surface and include Mercury, Venus, Earth, and Mars in our solar system. These planets are called "rocky" because of their solid, rocky compositions, as opposed to gas giants like Jupiter and Saturn, which are composed mainly of gases and have no solid surface. Their characteristics include relatively high densities, a variety of geological features, and the presence of atmospheres, albeit varying in thickness and composition.