Gas

Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).

A pure gas may be made up of individual atoms, elemental molecules made from one type of atom, or compound molecules made from a variety of atoms. A gas mixture contains a variety of pure gases.

What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the Human and some Humanoid observers.

This state of matter occurs between the liquid and plasma states.