👉 Fluid, in this context, refers to a state of continuous motion and transformation within a system. It encompasses various forms such as liquid, gas, or plasma, characterized by the ability to flow and change shape while maintaining a constant volume. This dynamic substance is driven by energy inputs, which can be thermal, mechanical, or electromagnetic, causing it to move and interact with its environment. The fluid's properties, such as viscosity and density, can vary greatly depending on temperature and pressure, influencing its behavior in different scenarios. Essentially, fluid represents a versatile and ever-changing medium that plays a crucial role in numerous natural processes and technological applications.