from The American Heritage® Dictionary of the English Language, 4th Edition
- n. 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.
- n. A synthetic compound that acts like a hormone in the body.
- n. Any of various similar substances found in plants and insects that regulate development.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any substance produced by one tissue and conveyed by the bloodstream to another to effect physiological activity.
- n. A synthetic compound with the same activity.
- n. Any similar substance in plants.
from the GNU version of the Collaborative International Dictionary of English
- n. A chemical substance formed in one organ and carried in the circulation to another organ on which it exerts a specific effect on cells at a distance from the producing cells.
- n. a chemical substance, whether natural or synthetic, that functions like a hormone in a living organism. .
- n. A substance that controls growth rate or differentiation in plants; also called phytohormone. The most well-known are the auxins that stimulate growth at the growing tips of plants, and control root formation and the dropping of leaves; and the gibberellins, which are used in agriculture to promote plant growth.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect
From Greek hormōn, present participle of hormān, to urge on, from hormē, impulse.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek ὁρμή (horme, "rapid motion forwards, onrush, onset, assault, impulse to do a thing, effort"), from ὁρμάω (hormao), ὁρμῶ (hormo, "to set in motion, to urge on, to cheer on, to make a start, to hasten on"). (Wiktionary)