The meaning of FLUID is having particles that easily move and change their relative position without a separation of the mass and that easily yield to pressure : capable of flowing.
fluid adjective (LIKELY TO CHANGE) If situations, ideas, or plans are fluid, they are not fixed and are likely to change, often repeatedly and unexpectedly:
FLUID definition: a substance, as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape. See examples of fluid used in a sentence.
Fluid ... In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (flow) under an applied shear stress, or external force. [1]
fluid (countable and uncountable, plural fluids) 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. quotations
adj. Hydraulics pertaining to a substance that easily changes its shape; capable of flowing. Hydraulics consisting of or pertaining to fluids. changing readily; shifting; not fixed, stable, or rigid: fluid movements. convertible into cash: fluid assets.