Any substance which can flow with relative ease, tends to assume the shape of its container, and obeys Bernoulli's principle; a liquid, gas or plasma. / A liquid (as opposed to a solid or gas).

(not comparable) Of or relating to fluid. / In a state of flux; subject to change. / Moving smoothly, or giving the impression of a liquid in motion. / (of an asset) Convertible into cash.

plural of fluid

The quality of being fluid.

(anatomy) Any liquid portion of the body, such as blood, urine, semen, saliva, especially when expelled.

any unit of volume, or system of such units

a ferrofluid that solidifies in the presence of a magnetic field

(zoology) In placental mammals, a fluid contained within the amnion membrane that surrounds a developing embryo or fetus.

(physics) a fluid whose stress at each point is linearly proportional to the strain rate at that point

(medicine) Any liquid discharge from a vagina.