absorption /absôrp″shən/ [L, absorptio] , 1. the incorporation of matter by other matter through chemical, molecular, or physical action, such as the dissolution of a gas in a liquid or the taking up of a liquid by a porous solid. 2. (in physiology) the passage of nutrients and substances across and into tissues, such as the passage of digested food molecules into intestinal cells or the passage of liquids into kidney tubules. Kinds include agglutinin absorption, cutaneous absorption, external absorption, intestinal absorption, parenteral absorption, pathological absorption. 3. (in radiology) the process of absorbing electromagnetic radiation in which a photon of energy is taken up by living or nonliving matter. −absorb, v.
