The phase of matter that has a fixed volume and a fixed shape is known as the solid phase. In solids, the particles are closely packed together in a regular pattern. This arrangement allows solids to maintain a definite shape and volume, as the particles are held firmly in place by strong forces of attraction.
Unlike liquids and gases, where particles can move more freely, the particles in a solid vibrate around fixed positions. This characteristic is what gives solids their rigidity and ability to retain their shape under normal conditions. Examples of solids include ice, wood, and metal.