👉 The term "fluid" in the context of physics and chemistry generally refers to a substance that can flow or change shape without breaking into discrete particles. Unlike solids, which have a fixed structure and volume, and gases, which expand to fill any container, fluids maintain a continuous state of matter. Liquids, a type of fluid, have a definite volume but take the shape of their container, allowing them to flow when subjected to force. This unique property of fluids enables them to move smoothly and adapt to different environments, making them essential in various natural processes and human applications.