a substance, esp a liquid or gas, that can flow freely, has no fixed shape, yields to pressure, and conforms to the shape of its container

a liquid in the body of an animal or plant

cerebrospinal fluid

said of liquids, gases, etc: capable of flowing, esp in having particles that easily change their relative position without separation of the mass and that yield to pressure

relating to fluids

fluid mechanics

said of a coupling or clutch: using a fluid to effect power transmission

said of a style of movement: smooth or easy; effortlessly graceful

said of plans, etc: not yet definite; capable of alteration or adaptation

said of assets: easily converted into cash; = liquid¹ (5)