Which state of matter is characterized by having a definite shape and volume?

The state of matter characterized by having a definite shape and volume is solid. In solids, the particles are closely packed together in a fixed arrangement, which allows them to maintain a set shape and volume. This structure results in strong intermolecular forces that hold the particles in place, preventing them from moving freely unlike in liquids and gases.

In contrast, liquids have a definite volume but no definite shape; they take the shape of their container. Gases do not have either a definite shape or volume, expanding to fill any container they occupy. Plasma, a state of matter found in stars and created under extreme conditions, also does not have a definite shape or volume. Therefore, solids are uniquely defined by their ability to retain both a fixed shape and volume.