👉 A fluid is a substance that takes the shape of its container while maintaining a constant volume. Unlike gases, which expand to fill any space and can take on any shape, fluids have a fixed volume. There are two main types: liquids and gases, but liquids are the only true fluids because they maintain a definite shape when confined to a container. Examples of fluids include water, oil, and blood, which can flow and change shape but always retain their volume.
