Medical Definition of hormone
1a: a product of living cells that circulates in body fluids (as blood) or sap and produces a specific often stimulatory effect on the activity of cells usually remote from its point of origin—called also internal secretion; see plant hormoneb: a synthetic substance that acts like a hormone
2: sex hormone
Seen and Heard
What made you want to look up hormone? Please tell us where you read or heard it (including the quote, if possible).