👉 A fluid, in the context of chemistry and biology, is a substance that takes the shape of its container while maintaining a constant volume. This means fluids neither expand to fill their container nor contract in response to changes in pressure, unlike gases which can both expand and compress. Common examples of fluids include water, blood, and oil. The term "fluid" also encompasses states like liquids and gases, which are subsets of fluids, characterized by their ability to flow and change shape under certain conditions.
