Thixotropic fluid, definition

Experimentally, it is sometimes difficult to detect differences between a shear-thinning liquid in which the viscosity decreases with increasing shear, and a thixotropic material in which the viscosity decreases with time, because of the combined shear and time effects that occur during a series of measurements. This is especially true if only a few data points are collected. In addition, most materials that are thixotropic are also shear thinning. In fact, one definition of a thixotropic fluid limits it to materials whose viscosity is a function of both shear rate and time (8). 

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