A cubic meter is a unit of volume in the metric system, commonly used to measure the space occupied by three-dimensional objects. It is defined as the volume of a cube with sides that are each one meter long. This measurement is useful in various fields, including construction, shipping, and environmental science. In practical terms, one cubic meter is equivalent to 1,000 liters, which helps in understanding quantities of liquids or gases. For example, a standard bathtub can hold about 0.3 to 0.4 cubic meters of water, illustrating how cubic meters can be applied in everyday situations.