👉 In a fluid context, typically referring to substances that can flow and change shape without breaking apart, the allowed fluids are primarily liquids and gases. Liquids maintain a definite volume but take the shape of their container, such as water or oil. Gases, on the other hand, have no definite volume or shape and expand to fill any container they are in, like nitrogen or carbon dioxide. Some specialized fluids, such as supercritical fluids (e.g., supercritical CO2), can exhibit properties of both liquids and gases under certain conditions but are generally not considered traditional allowed fluids in standard contexts.
