a unit of viscosity equal to the viscosity of a fluid that would require a shearing force of one dyne to move a square-centimeter area of either of two parallel layers of fluid one centimeter apart, with a velocity of one centimeter per second relative to the other layer, with the space between the layers being filled with the fluid in question. It is the ratio of the shear stress to the shear rate of a fluid, expressed in dyne seconds per square centimeter. 1 centipoise equals .01 poise.