di·ges·tion 
(dī-jĕschən, dĭ-)
(dī-jĕschən, dĭ-)n.
1.
a. The process by which food is converted into substances that can be absorbed and assimilated by a living organism. In most animals it is accomplished in the digestive tract by the mechanical and enzymatic breakdown of foods into simpler chemical compounds.
b. The ability to digest food.
2. Biochemistry The process of decomposing complex organic substances into simpler substances, as by the action of enzymes or bacteria.
3. Chemistry The process of softening or disintegrating by means of chemical action, heat, or moisture.
4. Assimilation of ideas or information; understanding.