n. The act or process of absorbing, or the state of being absorbed, in all the senses of the verb: as—n. In physiology, the process of taking up into the vascular system (venous or lymphatic) either food from the alimentary canal or inflammatory products and other substances from the various tissues. Plants absorb moisture and nutritive juices principally by their roots, but sometimes by their general surfaces, as in seaweeds, and carbonic acid by their leaves. Absorption of organic matter by leaves takes place in several insectivorous plants.n. n. In Herbart's pedagogic system, the gradual process of the apprehension of the manifold: a translation of the German vertiefung. Otherwise called concentration and self-estrangement.n. Specifically— In the absorption of gases, the volume of a gas which one volume of a liquid will dissolve.n. In optics, the constant K in the equation , where A0 is the amplitude of an incident ray, A1 its amplitude after penetrating to a depth of one wave-length in the absorbing medium, and e the base of natural logarithms.