In chemistry, absorption refers to the process through which one substance permeates another. An example of this is a liquid permeating a solid. Absorption can be physical or chemical, depending on whether it is non-reactive or reactive, respectively.
Absorption describes the process of assimilating or absorbing. Absorption can have distinct meanings based on the branch of science in which it is used. In biology, the word refers to the process of assimilating a substance into a cell or across a tissue or organ. This is accomplished through diffusion. An example of this process is the absorption of nutrients or chemicals by the human body.