The American Heritage® Dictionary of the English Language, 4th Edition
n. Any of several steroid hormones produced chiefly by the ovaries and responsible for promoting estrus and the development and maintenance of female secondary sex characteristics.
n. Any of a group of steroids that are secreted by the ovaries and function as female sex hormones.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics
Word Usage
"A lot of us like to fling around the word estrogen the way a pizza maker flings around dough, but the truth is that estrogen is a lot more complicated than that."