Anisotropic displacement parameters

The term anisotropic displacement parameters (abbreviated ADPs) is usualy used in referring to the individual atomic coefficients in the exponent of the factor that describes the effects of atomic motion and static displacement.

One should avoid using the term 'temperature factor', both because the phenomenon represented may not be due entirely to thermal motion and because that phrase has in the past been used in several quite distinct senses

Reference

https://doi.org/10.1107/S0108767396005697