The gaseous state is a scientific term that describes the state of matter in which substances have no fixed shape or volume but expand to fill their container. There are several alternative phrases that can be used to describe this state of matter, including vapor state, gas phase, and aeriform state. The term vapor state is often used to describe the state of matter that results from the evaporation of a liquid or solid at a specific temperature. Gas phase is a commonly used synonym that simply refers to the gaseous state, particularly in chemistry. Finally, aeriform state is a more literary phrase that evokes a sense of the ethereal, airy quality of the gaseous state.