Understanding Secretions: Definition, Types & Examples

Secretion, in biology, is a process in which a substance (secretion) is passed out from a cell, a gland, or a tissue. Secretion is also a substance secreted.

Secretions are generally distinguished from excretions, although this distinction is not always clear-cut. Excretions are waste products that are given off by an organism, whereas secretions are substances that are produced and released for a specific purpose. For example, sweat is an excretion, while saliva is a secretion.