- In general, the resistance to flow or alteration of shape by any substance as a result of molecular cohesion; most frequently applied to liquids as the resistance of a fluid to flow because of a shearing force. [L. viscositas, fr. viscosus, viscous]- absolute v. force per unit area applied tangentially to a fluid, causing unit rate of displacement of parallel planes separated by a unit distance; units in CGS system : poise.- anomalous v. the viscous behavior of nonhomogenous fluids or suspensions, e.g., blood, in which the apparent v. increases as flow or shear rate decreases toward zero.- apparent v. the v. calculated from Poiseuille law at any particular flow and tube diameter; it is used for suspensions, such as blood, that exhibit anomalous v. and the Fahraeus-Lindqvist effect.- dynamic v. (μ) the internal or molecular frictional resistance of a fluid by Newton law of v. as the ratio of the applied force per unit area to the relative velocity of adjacent fluid layers (produced by the force).- kinematic v. (ν, Υ) a measure used in studies of fluid flow; it is the dynamic v., μ, in poises, divided by the density of the material; unit; stoke.- newtonian v. the v. characteristics of a newtonian fluid.- relative v. the ratio of the v. of a solution or dispersion to the v. of the solvent or continuous phase.
* * *1) the quality of being viscous esp the property of resistance to flow in a fluid or semifluid2) the ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the direction of flow of a liquid called also coefficient of viscosity
* * *vis·cos·i·ty (vis-kosґĭ-te) resistance to flow; a physical property of a substance that depends on the friction of its component molecules as they slide past one another.
Medical dictionary. 2011.