Solar, for instance, is less useful in the long dark night of the northern winter.Washington Post (Aug 14, 2015) sol (sun) + ar (suffix forming adjectives) As the roots and definition show, the word should be an adjective, but the example sentence uses it as a shortened form of the noun phrase solar energy..
Disproportionality is the overrepresentation of a particular race or cultural group in a program or system compared to their representation in the general population. Disproportionality affects all systems such as the educational, mental health and judicial systems creating additional costs within these areas.
For other uses, see Diffusivity (disambiguation). Diffusivity or diffusion coefficient is a proportionality constant between the molar flux due to molecular diffusion and the gradient in the concentration of the species (or the driving force for diffusion). Diffusivity is encountered in Fick's law and numerous other equations of physical chemistry.