A three-dimensional object is termed "solid." Solids have three dimensions: length, width, and height, distinguishing them from two-dimensional shapes, which possess only length and width. Solids can be classified in various ways, primarily as geometric shapes such as cubes, spheres, and pyramids, or by their material properties, like metals, plastics, or biological structures. The study of solids is crucial in many fields, including physics, engineering, and architecture, as it helps in understanding how these objects behave in space, their structural integrity, and their interactions with forces such as gravity.