An organ in the body which produces a secretion used by the organism or even eliminated from it: The thyroid gland produces a substance which a person needs to regulate growth, among other factors.

A triangular gland situated on top of the kidney; suprarenal gland: The cortex of the adrenal gland (outer part) secretes various steroid hormones and other hormones that control salt and water metabolism and regulate the use of carbohydrates, proteins, and fats.

The medulla, the inner part of the adrenal gland, secretes the hormones adrenaline and noradrenaline which, during times of stress, prepare the body for "fight or flight".

One of a heterogeneous group of food bodies with a pearl-like luster and high concentration of lipids (fatty acids), apparently used by plants to attract and to support ants.