- The definition of a hormone is a substance formed in an organ or tissue in the body of a plant or animal and then transported by body fluid to another organ or tissue for a specific action.
An example of a hormone is estrogen in humans.
hormone definition by Webster's New World
- a substance formed in some organ of the body, as the adrenal glands, the pituitary, etc., and carried by a body fluid to another organ or tissue, where it has a specific effect: now often prepared synthetically
- a similar substance produced in a plant, as an auxin
Origin: ; from Classical Greek hormōn, present participle of horman, to stimulate, excite ; from hormē, impulse ; from Indo-European base an unverified form ser-, to stream from source Sanskrit sará-, fluid, Classical Latin serum, whey
hormone definition by American Heritage Dictionary
- a. A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism.b. A synthetic compound that acts like a hormone in the body.
- Any of various similar substances found in plants and insects that regulate development.
Origin: From Greek hormōn, present participle of hormān, to urge on, from hormē, impulse; see er-1 in Indo-European roots.
- hor·monˈal , hor·monˈic adjective
- hor·monˈal·ly adverb
hormone - Medical Definition
- A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism.
- A synthetic compound that acts like a hormone in the body.
- hormonal adjective
hormone - Science Definition
- A chemical substance secreted by an endocrine gland or group of endocrine cells that acts to control or regulate specific physiological processes, including growth, metabolism, and reproduction. Most hormones are secreted by endocrine cells in one part of the body and then transported by the blood to their target site of action in another part, though some hormones act only in the region in which they are secreted. Many of the principal hormones of vertebrates, such as growth hormone and thyrotropin, are secreted by the pituitary gland, which is in turn regulated by neurohormone secretions of the hypothalamus. Hormones also include the endorphins, androgens, and estrogens. See more at endocrine gland.
- A substance that is synthesized by a plant part and acts to control or regulate the growth and development of the plant. The action and effectiveness of a hormone can depend on the hormone's chemical structure, its amount in relation to other hormones that have competing or opposing effects, and the ways in which it interacts with chemical receptors in various plant parts. Auxins, cytokinins, gibberellins, abscisic acid, and ethylene are plant hormones.