digestion
di.ges.tion \di--'jes(h)-ch*n, d*-\ n : the action, process, or power of digesting : as : the process of making food absorbable by dissolving it and breaking it down into simpler chemical compounds that occurs in the living body chiefly through the action of enzymes secreted into the alimentary canal : the process in sewage treatment by which organic matter in sludge is de composed by anaerobic bacteria with the release of a burnable mixture of gases