👉 A fluid, in the context of physics and engineering, is a substance that flows easily under applied stress or pressure, exhibiting properties of both liquids and gases. Unlike solids, which have a fixed shape but not volume, or gases, which expand to fill any container, fluids maintain a constant volume but take the shape of their container. This unique characteristic is due to the intermolecular forces within the fluid, which allow molecules to move past one another while still maintaining cohesion. Examples of fluids include water, air, and oils, which can flow and change shape but retain their volume.
