Absorption

• (acoustics)

1. The property of a material that changes acoustic energy into (usually) heat energy. A material or surface that absorbs sound waves does not reflect them. Absorption of a given material is frequency dependent as well as being affected by the size, shape, location, and mounting method used. Source: Church Audio & Acoustics Glossary
2. In acoustics, the changing of sound energy to heat. Source: http://www.owenscorning.com/around/sound/glossary.asp

• (biology) the taking up of substances or their passage through the walls of cells Source: Noland, George B. 1983. General Biology, 11th Edition. St. Louis, MO. C. V. Mosby
• (biotechnology) The process of absorbing; specifically:

1. In physiology, it refers to the movement of liquids and solutes into cells by way of diffusion or osmosis.
2. In chemistry, it refers to the drawing of a gas or liquid into the pores of a permeable solid.
3. In immunology, it refers to a process in which an antigen or antibody is used to pull an analogous antigen or antibody out of a solution.

• (environment) The uptake of water, other fluids, or dissolved chemicals by a cell or an organism (as tree roots absorb dissolved nutrients in soil.) Source: Terms of the Environment

Compare adsorption.