Absorbability is a term that refers to how easily a substance can be absorbed or assimilated. There are several synonyms that can be used interchangeably with absorbability, including permeability, assimilability, and absorptivity. Permeability refers to the ability of a material to allow fluids or gases to pass through it. Assimilability refers to the ease with which a substance can be taken up into the body and converted into a usable form. Absorptivity refers to the ability of a material to absorb light or other forms of energy. All of these terms are related to the concept of absorbability and can be used to describe the degree to which a substance can be absorbed or assimilated.