Definition of fluids:
(n) :
A liquid (as opposed to a solid or gas).
(n) :
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.
(n) :
(specifically, medicine, colloquial, typically in the plural) Intravenous fluids.
(adj) :
In a state of flux; subject to change.
(adj) :
Moving smoothly, or giving the impression of a liquid in motion.
(adj) :
(not comparable) Of or relating to fluid.