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.
2. Any of various similar substances found in plants and insects that regulate development.
[From Greek hormōn, present participle of hormān, to urge on, from hormē, impulse; see er-1 in the Appendix of Indo-European roots.]
hor·monal (-mōnəl), hor·monic (-mŏnĭk) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.